Md.Ariful Hoque - Academia.edu (original) (raw)

Papers by Md.Ariful Hoque

The Journal of Developing Areas, 2019

Much of the past studies on the determinants of financial condition argue that local government f... more Much of the past studies on the determinants of financial condition argue that local government financial condition is a function of revenue capacity and spending pressure represented by various socioeconomic factors and have exhibited inconclusive results. In response, this study argues that the effects of socioeconomic and demographic factors on financial conditions depend on the context in which the local government operates. The inconclusive results found in the literature suggest the need for investigating the effects of these factors in various contexts in order to understand how they operate. This research examines the relationships of spending pressure and revenue capacity with financial conditions of municipal organisations from a developing country's context. Spending pressure indicates the demands for municipal services and is represented by population size, population density and disaster susceptibility. Revenue capacity demonstrates the ability of municipal organizations in obtaining resources for public purposes. Based on theoretical and empirical studies from the literature, this study develops hypotheses and tests them using data from a random sample of 93 municipal organisations from Bangladesh. Analysing data by applying a linear regression model, the paper finds empirical supports for positive relationships of disaster susceptibility and revenue capacity but negative relationship of population size with municipal financial conditions. Such a relationship of population density is found to be positive but insignificant, which contradicts with the results found in the literature. Theoretically, this study enhances the existing literature as it facilitates a better understanding on how the socioeconomic and demographic variables interact with municipal financial conditions from a developing country context. The empirical findings can be of great significance for both managers and politicians. While municipal managers can find the information of this study useful in improving their organizational financial conditions by exploiting their relationships with socioeconomic and demographic factors to generate appropriate level of revenues and control expenditures, policy makers can derive insights from this study to devise effective financial transfer policies for maintaining sustainability of local government services.

ACS Sustainable Chemistry & Engineering, 2017

Development of highly durable electrocatalysts for oxygen reduction reaction (ORR) is critical fo... more Development of highly durable electrocatalysts for oxygen reduction reaction (ORR) is critical for proton exchange membrane fuel cells. Herein, we report the synthesis, characterization, and electrochemical performance of 1D sulfur-doped carbon nanotubes (S-CNT) supported 1D Pt nanowires (PtNW/ S-CNT). PtNW/S-CNT synthesized by a modified solvothermal method possesses a unique web-like 3D architecture that is beneficial for oxygen reduction. We demonstrate that PtNW/S-CNT exhibits impressive activity retention under potential cycling between 0.05 and 1.5 V vs RHE over 3000 cycles. The reductions in electrochemically active surface area (ECSA, 7% loss) and mass activity (19% loss) of PtNW/S-CNT after accelerated durability testing (ADT) are found to be much lower than the dramatic losses observed with commercial Pt/C (>99% loss in ECSA and mass activity) under identical conditions. The PtNW/S-CNT catalyst also shows very high specific activity (1.61 mA cm −2) in comparison to Pt/C (0.24 mA cm −2).

The Journal of Developing Areas, 2017

Studies on local governmental financial conditions are focused on developing tools for detecting ... more Studies on local governmental financial conditions are focused on developing tools for detecting and avoiding potential financial problems. These studies are confined mostly in self-governed local government entities in the western world. This research seeks to measure financial conditions of local government organisations in Bangladesh. Municipalities, one of the two types of urban local government, play an important role in providing a range of services and carrying out certain socioeconomic objectives in Bangladesh. Using financial data from a representative sample of 72 municipalities, this research measures and compares municipal financial conditions of local government municipalities in Bangladesh. A composite index of eleven indicators was developed under four dimensions, viz., short term solvency, budgetary solvency, service level solvency and long term solvency by following the relevant literature on local government financial conditions as well as keeping consistency with data availability. This composite index was applied to measure the financial conditions of the three classes (Class I, II and III) of municipalities in Bangladesh for a period 2007 to 2015. Results obtained indicate that there are differences across these three types of municipalities in their overall financial conditions as well as in their short term, long term and service level solvencies. The index measure explains the financial and operational strengths and weaknesses of municipalities, a clear understanding of which is necessary for improving their performance on sustainable basis. The result of this research is likely to have implications for devising policies for making municipalities more effective organizations. While, the findings will help municipal management to focus their operations to improve their financial and service performance, policy makers at the central level will find it as a useful tool in devising policies for equitable distribution of resources among municipal organizations.

Journal of Materials Chemistry A, 2015

Shape controlled cobalt disulfide octahedron nanoparticles are grown on nitrogen/sulfur-doped car... more Shape controlled cobalt disulfide octahedron nanoparticles are grown on nitrogen/sulfur-doped carbon nanotube-graphene composites as active non-precious oxygen reduction catalysts.

RSC Advances, 2016

Post-heat treatment of dealloyed Pt–Ni nanoparticles on sulfur-doped graphene for PEM fuel cell c... more Post-heat treatment of dealloyed Pt–Ni nanoparticles on sulfur-doped graphene for PEM fuel cell cathode catalysis exhibit greatly improved activity and electrochemically active surface area retention over Pt/C in half-cell conditions.

J. Mater. Chem. A, 2015

Grain boundaries are revealed to be a primary source of one-dimensional Pt nanostructure instabil... more Grain boundaries are revealed to be a primary source of one-dimensional Pt nanostructure instability by comparing the structural evolution processes of rationally synthesized tubular structures with Pt/C.

Advanced Functional Materials, 2014

Unique sulfur-doped graphene-supported platinum nanoparticles prepared by Z. Chen and co-workers ... more Unique sulfur-doped graphene-supported platinum nanoparticles prepared by Z. Chen and co-workers provide excellent oxygen reduction activity and stability, rendering them highly attractive electrode materials for fuel cell applications. On page 4325, the enhancements arise due to specific interactions between the sulfur dopant atoms and the platinum nanoparticles, leading to a "tethering" effect that increases the stability and modulates the electronic properties that improve the activity.

Sci. Rep., 2013

Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemi... more Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2-5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2-3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst.

ACS Catalysis, 2014

The development of unique, reliable, and scalable synthesis strategies for producing heteroatom-d... more The development of unique, reliable, and scalable synthesis strategies for producing heteroatom-doped nanostructured carbon materials with improved activity toward the electrochemical oxygen reduction reaction (ORR) occurring in metal−air batteries and fuel cells presents an intriguing technological challenge in the field of catalysis. Herein, we prepare unique graphene−carbon nanotube composites (GC) doped sequentially with both nitrogen and sulfur (GC-NLS) and subject them to extensive physicochemical characterization and electrochemical evaluation toward the ORR in an alkaline electrolyte. GC-NLS provides ORR onset potential increases of 50 and 70 mV in comparison to those of dual-doped individual graphene and carbon nanotubes, respectively. This highlights the significant synergistic effects that arise because of the nanocomposite arrangement, consisting of highly graphitized carbon nanotubes assembled on the surface of graphene sheets. The addition of sulfur as a co-dopant is also highly beneficial, providing an 80 mV increase in the ORR onset potential in comparison to that of GC nanocomposites doped with only nitrogen. Excellent electrochemical stability of GC-NLS is also observed through 5000 electrode potential cycles, indicating the promising potential of this new class of dual-doped GC nanocomposites as ORR catalysts.

Nano Energy, 2014

One-dimensional platinum-cobalt alloy nanowires (PtCoNWs) are prepared by electrospinning, which ... more One-dimensional platinum-cobalt alloy nanowires (PtCoNWs) are prepared by electrospinning, which provides a versatile platform for the synthesis of nanowires with tunable diameters and atomic compositions. PtCoNWs with a near unity stoichiometric ratio, excellent atomic distribution and an average diameter of 28 nm were evaluated for oxygen reduction reaction (ORR) activity in 0.1 M HClO 4 electrolyte. Over a four-fold enhancement in Pt mass-based activity at an electrode potential of 0.9 V vs. RHE is obtained in comparison to pure PtNWs, highlighting the beneficial impact of the alloying structure. A near 7-fold specific activity increase is also observed in comparison to commercial Pt/C catalyst, along with improved electrochemically active surface area retention through repetitive (1000) potential cycles. Electrospinning is thereby an attractive approach to prepare morphology and composition controlled PtCoNWs that could potentially one day replace conventional nanoparticle catalysts.

DECISION, 2014

ABSTRACT WORKING CAPITAL MANAGEMENT AND PROFITABILITY: A COMPARATIVE ANALYSIS OF LISTED MANUFACTU... more ABSTRACT WORKING CAPITAL MANAGEMENT AND PROFITABILITY: A COMPARATIVE ANALYSIS OF LISTED MANUFACTURING AND PLANTATION COMPANIES IN COLOMBO STOCK EXCHANGE IN SRI LANKA Abstract Working capital management is a vital role in the firms’ financial management decision making. When, working capital is managed improperly, allocating more than enough of it will render management non-efficient and reduce the benefits of short term investments. On the other hand, if working capital is too low, the company may miss a lot of profitable investment opportunities or suffer short term liquidity crisis, leading to degradation of company credit, as it cannot respond effectively to temporary capital requirements. The prime objective of this research is to identify the linkage between the working capital management and profitability and its impact on profitability. And the comparison among the listed manufacturing and plantation companies is also another objective. The relationship between the working capital management and profitability is examined using Pearson’s correlation analyses and the effects on profitability is found out using the regression analyses by using a sample of annual financial statements of listed manufacturing and plantation companies in Colombo Stock Exchange in Sri Lanka for the period of 2007-2011. The study measures financial performance in terms of Net Profit Margin (NPM), Return on Equity (ROE), and Return on Assets (ROA) where as working capital management is measured in terms of the Cash Conversion Cycle (CCC) and its components (Number of Days Accounts Receivables (NDAR), Number of Days Accounts Payables (NDAP) and Number of days Inventory (NDI). The results of this study showed that there is a statistically significance relationship between financial performance and working capital management of the manufacturing companies and plantation companies. Ultimately the finance managers can create profits for their companies by handling correctly the CCC and keeping NDAR, NDAP and NDI to an optimum level. Keywords: Working Capital Management; Profitability: Manufacturing Companies; Plantation Companies

Electrochimica Acta, 2014

Unique tin oxide-mesoporous carbon (SnO 2-CMK-3) composites have been synthesized as platinum nan... more Unique tin oxide-mesoporous carbon (SnO 2-CMK-3) composites have been synthesized as platinum nanoparticle electrocatalyst supports for low temperature fuel cell applications. In comparison with state-of-the-art commercial carbon-supported platinum (Pt/C) and pure CMK-3-supported platinum (Pt/CMK-3), Pt/SnO 2-CMK3 demonstrated improved Pt-mass and surface area based ethanol oxidation reaction (EOR) activity through half-cell electrochemical investigations, providing a 64.7 and 97.6 mV reduction in overpotential at 100 mA mg −1 Pt upon comparison to Pt/CMK-3 and commercial Pt/C. Furthermore, improvements to the oxygen reduction reaction (ORR) kinetics were observed, with Pt/SnO 2-CMK3 providing a kinetic current density of 3.40 mAcm −2 at an electrode potential of 0.9 V vs RHE. The improved performance of Pt/SnO 2-CMK-3 for EOR and ORR was attributed to the beneficial impact of the support properties, along with potential interactions occurring between the support and catalyst particles. Complemented by extensive physicochemical characterization, these unique materials show high promise for application in low temperature fuel cells.

Advanced Functional Materials, 2014

reaction (ORR) occurring at the cathode. Conventional PEMFC systems employ platinum (Pt) based ca... more reaction (ORR) occurring at the cathode. Conventional PEMFC systems employ platinum (Pt) based catalysts, which to date have been the only materials capable of facilitating the ORR at rates practical, although still insuffi cient for PEMFC operation. The widespread commercialization and deployment of PEMFCs into advanced sustainable energy infrastructures including the automotive sector is still limited by three primary factors: i) high cost, ii) insuffi cient performance, and iii) low durability. [ 1,2 ] At the root of these limitations lies the aforementioned expensive Pt catalyst materials employed; generally consisting of Pt nanoparticles (≈2-3 nm) uniformly distributed on high surface area carbon black supports (Pt/C). Although signifi cant improvements to state-of-the-art Pt/C catalysts and electrode designs for automobile PEMFCs has been realized in recent years, an immense challenge in achieving the 2017 technical targets set by the United States Department of Energy still remains at the current state of catalyst technology. The targets state that by 2017, the total Pt loading (anode and cathode) must be reduced to below 0.125 mg cm −2 coupled with 5000 h of operational stability under simulated drive cycles. [ 3 ] Specifically, Pt/C is known to degrade under the harsh oxidizing conditions encountered at the PEMFC cathode due to corrosion of the carbon support materials, or by agglomeration and/or dissolution of the platinum nanoparticles resulting from weak interactions with the catalyst supports. [ 4 ] This in turn leads to a sharp loss in available electrochemically active surface areas (ECSA) and by extension fuel cell performance. A common approach to improve catalyst stability and activity has involved the design of non-conventional catalyst supports, including transition metal oxides and nitrides; [ 5-8 ] or alternative carbon supports doped with heteroatoms such as nitrogen to enhance the interaction and synergy between the catalyst particle and its support. [ 9,10 ] It is well understood that the structure and properties of the support materials will directly govern the performance and stability of the catalyst materials. There still however remains a lack of fundamental understanding regarding the exact nature of these particular catalyst-support

The Journal of Developing Areas, 2019

Much of the past studies on the determinants of financial condition argue that local government f... more Much of the past studies on the determinants of financial condition argue that local government financial condition is a function of revenue capacity and spending pressure represented by various socioeconomic factors and have exhibited inconclusive results. In response, this study argues that the effects of socioeconomic and demographic factors on financial conditions depend on the context in which the local government operates. The inconclusive results found in the literature suggest the need for investigating the effects of these factors in various contexts in order to understand how they operate. This research examines the relationships of spending pressure and revenue capacity with financial conditions of municipal organisations from a developing country's context. Spending pressure indicates the demands for municipal services and is represented by population size, population density and disaster susceptibility. Revenue capacity demonstrates the ability of municipal organizations in obtaining resources for public purposes. Based on theoretical and empirical studies from the literature, this study develops hypotheses and tests them using data from a random sample of 93 municipal organisations from Bangladesh. Analysing data by applying a linear regression model, the paper finds empirical supports for positive relationships of disaster susceptibility and revenue capacity but negative relationship of population size with municipal financial conditions. Such a relationship of population density is found to be positive but insignificant, which contradicts with the results found in the literature. Theoretically, this study enhances the existing literature as it facilitates a better understanding on how the socioeconomic and demographic variables interact with municipal financial conditions from a developing country context. The empirical findings can be of great significance for both managers and politicians. While municipal managers can find the information of this study useful in improving their organizational financial conditions by exploiting their relationships with socioeconomic and demographic factors to generate appropriate level of revenues and control expenditures, policy makers can derive insights from this study to devise effective financial transfer policies for maintaining sustainability of local government services.

ACS Sustainable Chemistry & Engineering, 2017

Development of highly durable electrocatalysts for oxygen reduction reaction (ORR) is critical fo... more Development of highly durable electrocatalysts for oxygen reduction reaction (ORR) is critical for proton exchange membrane fuel cells. Herein, we report the synthesis, characterization, and electrochemical performance of 1D sulfur-doped carbon nanotubes (S-CNT) supported 1D Pt nanowires (PtNW/ S-CNT). PtNW/S-CNT synthesized by a modified solvothermal method possesses a unique web-like 3D architecture that is beneficial for oxygen reduction. We demonstrate that PtNW/S-CNT exhibits impressive activity retention under potential cycling between 0.05 and 1.5 V vs RHE over 3000 cycles. The reductions in electrochemically active surface area (ECSA, 7% loss) and mass activity (19% loss) of PtNW/S-CNT after accelerated durability testing (ADT) are found to be much lower than the dramatic losses observed with commercial Pt/C (>99% loss in ECSA and mass activity) under identical conditions. The PtNW/S-CNT catalyst also shows very high specific activity (1.61 mA cm −2) in comparison to Pt/C (0.24 mA cm −2).

The Journal of Developing Areas, 2017

Studies on local governmental financial conditions are focused on developing tools for detecting ... more Studies on local governmental financial conditions are focused on developing tools for detecting and avoiding potential financial problems. These studies are confined mostly in self-governed local government entities in the western world. This research seeks to measure financial conditions of local government organisations in Bangladesh. Municipalities, one of the two types of urban local government, play an important role in providing a range of services and carrying out certain socioeconomic objectives in Bangladesh. Using financial data from a representative sample of 72 municipalities, this research measures and compares municipal financial conditions of local government municipalities in Bangladesh. A composite index of eleven indicators was developed under four dimensions, viz., short term solvency, budgetary solvency, service level solvency and long term solvency by following the relevant literature on local government financial conditions as well as keeping consistency with data availability. This composite index was applied to measure the financial conditions of the three classes (Class I, II and III) of municipalities in Bangladesh for a period 2007 to 2015. Results obtained indicate that there are differences across these three types of municipalities in their overall financial conditions as well as in their short term, long term and service level solvencies. The index measure explains the financial and operational strengths and weaknesses of municipalities, a clear understanding of which is necessary for improving their performance on sustainable basis. The result of this research is likely to have implications for devising policies for making municipalities more effective organizations. While, the findings will help municipal management to focus their operations to improve their financial and service performance, policy makers at the central level will find it as a useful tool in devising policies for equitable distribution of resources among municipal organizations.

Journal of Materials Chemistry A, 2015

Shape controlled cobalt disulfide octahedron nanoparticles are grown on nitrogen/sulfur-doped car... more Shape controlled cobalt disulfide octahedron nanoparticles are grown on nitrogen/sulfur-doped carbon nanotube-graphene composites as active non-precious oxygen reduction catalysts.

RSC Advances, 2016

Post-heat treatment of dealloyed Pt–Ni nanoparticles on sulfur-doped graphene for PEM fuel cell c... more Post-heat treatment of dealloyed Pt–Ni nanoparticles on sulfur-doped graphene for PEM fuel cell cathode catalysis exhibit greatly improved activity and electrochemically active surface area retention over Pt/C in half-cell conditions.

J. Mater. Chem. A, 2015

Grain boundaries are revealed to be a primary source of one-dimensional Pt nanostructure instabil... more Grain boundaries are revealed to be a primary source of one-dimensional Pt nanostructure instability by comparing the structural evolution processes of rationally synthesized tubular structures with Pt/C.

Advanced Functional Materials, 2014

Unique sulfur-doped graphene-supported platinum nanoparticles prepared by Z. Chen and co-workers ... more Unique sulfur-doped graphene-supported platinum nanoparticles prepared by Z. Chen and co-workers provide excellent oxygen reduction activity and stability, rendering them highly attractive electrode materials for fuel cell applications. On page 4325, the enhancements arise due to specific interactions between the sulfur dopant atoms and the platinum nanoparticles, leading to a "tethering" effect that increases the stability and modulates the electronic properties that improve the activity.

Sci. Rep., 2013

Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemi... more Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2-5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2-3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst.

ACS Catalysis, 2014

The development of unique, reliable, and scalable synthesis strategies for producing heteroatom-d... more The development of unique, reliable, and scalable synthesis strategies for producing heteroatom-doped nanostructured carbon materials with improved activity toward the electrochemical oxygen reduction reaction (ORR) occurring in metal−air batteries and fuel cells presents an intriguing technological challenge in the field of catalysis. Herein, we prepare unique graphene−carbon nanotube composites (GC) doped sequentially with both nitrogen and sulfur (GC-NLS) and subject them to extensive physicochemical characterization and electrochemical evaluation toward the ORR in an alkaline electrolyte. GC-NLS provides ORR onset potential increases of 50 and 70 mV in comparison to those of dual-doped individual graphene and carbon nanotubes, respectively. This highlights the significant synergistic effects that arise because of the nanocomposite arrangement, consisting of highly graphitized carbon nanotubes assembled on the surface of graphene sheets. The addition of sulfur as a co-dopant is also highly beneficial, providing an 80 mV increase in the ORR onset potential in comparison to that of GC nanocomposites doped with only nitrogen. Excellent electrochemical stability of GC-NLS is also observed through 5000 electrode potential cycles, indicating the promising potential of this new class of dual-doped GC nanocomposites as ORR catalysts.

Nano Energy, 2014

One-dimensional platinum-cobalt alloy nanowires (PtCoNWs) are prepared by electrospinning, which ... more One-dimensional platinum-cobalt alloy nanowires (PtCoNWs) are prepared by electrospinning, which provides a versatile platform for the synthesis of nanowires with tunable diameters and atomic compositions. PtCoNWs with a near unity stoichiometric ratio, excellent atomic distribution and an average diameter of 28 nm were evaluated for oxygen reduction reaction (ORR) activity in 0.1 M HClO 4 electrolyte. Over a four-fold enhancement in Pt mass-based activity at an electrode potential of 0.9 V vs. RHE is obtained in comparison to pure PtNWs, highlighting the beneficial impact of the alloying structure. A near 7-fold specific activity increase is also observed in comparison to commercial Pt/C catalyst, along with improved electrochemically active surface area retention through repetitive (1000) potential cycles. Electrospinning is thereby an attractive approach to prepare morphology and composition controlled PtCoNWs that could potentially one day replace conventional nanoparticle catalysts.

DECISION, 2014

ABSTRACT WORKING CAPITAL MANAGEMENT AND PROFITABILITY: A COMPARATIVE ANALYSIS OF LISTED MANUFACTU... more ABSTRACT WORKING CAPITAL MANAGEMENT AND PROFITABILITY: A COMPARATIVE ANALYSIS OF LISTED MANUFACTURING AND PLANTATION COMPANIES IN COLOMBO STOCK EXCHANGE IN SRI LANKA Abstract Working capital management is a vital role in the firms’ financial management decision making. When, working capital is managed improperly, allocating more than enough of it will render management non-efficient and reduce the benefits of short term investments. On the other hand, if working capital is too low, the company may miss a lot of profitable investment opportunities or suffer short term liquidity crisis, leading to degradation of company credit, as it cannot respond effectively to temporary capital requirements. The prime objective of this research is to identify the linkage between the working capital management and profitability and its impact on profitability. And the comparison among the listed manufacturing and plantation companies is also another objective. The relationship between the working capital management and profitability is examined using Pearson’s correlation analyses and the effects on profitability is found out using the regression analyses by using a sample of annual financial statements of listed manufacturing and plantation companies in Colombo Stock Exchange in Sri Lanka for the period of 2007-2011. The study measures financial performance in terms of Net Profit Margin (NPM), Return on Equity (ROE), and Return on Assets (ROA) where as working capital management is measured in terms of the Cash Conversion Cycle (CCC) and its components (Number of Days Accounts Receivables (NDAR), Number of Days Accounts Payables (NDAP) and Number of days Inventory (NDI). The results of this study showed that there is a statistically significance relationship between financial performance and working capital management of the manufacturing companies and plantation companies. Ultimately the finance managers can create profits for their companies by handling correctly the CCC and keeping NDAR, NDAP and NDI to an optimum level. Keywords: Working Capital Management; Profitability: Manufacturing Companies; Plantation Companies

Electrochimica Acta, 2014

Unique tin oxide-mesoporous carbon (SnO 2-CMK-3) composites have been synthesized as platinum nan... more Unique tin oxide-mesoporous carbon (SnO 2-CMK-3) composites have been synthesized as platinum nanoparticle electrocatalyst supports for low temperature fuel cell applications. In comparison with state-of-the-art commercial carbon-supported platinum (Pt/C) and pure CMK-3-supported platinum (Pt/CMK-3), Pt/SnO 2-CMK3 demonstrated improved Pt-mass and surface area based ethanol oxidation reaction (EOR) activity through half-cell electrochemical investigations, providing a 64.7 and 97.6 mV reduction in overpotential at 100 mA mg −1 Pt upon comparison to Pt/CMK-3 and commercial Pt/C. Furthermore, improvements to the oxygen reduction reaction (ORR) kinetics were observed, with Pt/SnO 2-CMK3 providing a kinetic current density of 3.40 mAcm −2 at an electrode potential of 0.9 V vs RHE. The improved performance of Pt/SnO 2-CMK-3 for EOR and ORR was attributed to the beneficial impact of the support properties, along with potential interactions occurring between the support and catalyst particles. Complemented by extensive physicochemical characterization, these unique materials show high promise for application in low temperature fuel cells.

Advanced Functional Materials, 2014

reaction (ORR) occurring at the cathode. Conventional PEMFC systems employ platinum (Pt) based ca... more reaction (ORR) occurring at the cathode. Conventional PEMFC systems employ platinum (Pt) based catalysts, which to date have been the only materials capable of facilitating the ORR at rates practical, although still insuffi cient for PEMFC operation. The widespread commercialization and deployment of PEMFCs into advanced sustainable energy infrastructures including the automotive sector is still limited by three primary factors: i) high cost, ii) insuffi cient performance, and iii) low durability. [ 1,2 ] At the root of these limitations lies the aforementioned expensive Pt catalyst materials employed; generally consisting of Pt nanoparticles (≈2-3 nm) uniformly distributed on high surface area carbon black supports (Pt/C). Although signifi cant improvements to state-of-the-art Pt/C catalysts and electrode designs for automobile PEMFCs has been realized in recent years, an immense challenge in achieving the 2017 technical targets set by the United States Department of Energy still remains at the current state of catalyst technology. The targets state that by 2017, the total Pt loading (anode and cathode) must be reduced to below 0.125 mg cm −2 coupled with 5000 h of operational stability under simulated drive cycles. [ 3 ] Specifically, Pt/C is known to degrade under the harsh oxidizing conditions encountered at the PEMFC cathode due to corrosion of the carbon support materials, or by agglomeration and/or dissolution of the platinum nanoparticles resulting from weak interactions with the catalyst supports. [ 4 ] This in turn leads to a sharp loss in available electrochemically active surface areas (ECSA) and by extension fuel cell performance. A common approach to improve catalyst stability and activity has involved the design of non-conventional catalyst supports, including transition metal oxides and nitrides; [ 5-8 ] or alternative carbon supports doped with heteroatoms such as nitrogen to enhance the interaction and synergy between the catalyst particle and its support. [ 9,10 ] It is well understood that the structure and properties of the support materials will directly govern the performance and stability of the catalyst materials. There still however remains a lack of fundamental understanding regarding the exact nature of these particular catalyst-support