Julie Anne Del Rosario - Academia.edu (original) (raw)
Papers by Julie Anne Del Rosario
Applied Catalysis B: Environmental, 2021
RSC Advances, 2021
Alkaline earth atom dopants on graphene induce work function tuning and spin polarized electronic... more Alkaline earth atom dopants on graphene induce work function tuning and spin polarized electronic properties by ionic bonding.
Journal of Energy Storage, 2021
Abstract The increasing demand for batteries’ application in grid-balancing, electric vehicles, a... more Abstract The increasing demand for batteries’ application in grid-balancing, electric vehicles, and portable electronics has prompted research efforts on improving their performance and safety features. The improvement of batteries involves the comparison of multiple battery designs and the determination of electrochemical and thermal property distributions at the continuum scale. This is achieved by using multiphysics modeling for investigatory battery research, as conventional experimental approaches would be costly and impractical. The fundamental electrochemical models for these batteries have been established, hence, new models are being developed for specific applications, such as thermal runaway and battery degradation in lithium-ion batteries, gas evolution in lead-acid batteries, and vanadium crossover in vanadium redox flow batteries. The inclusion of new concepts in multiphysics modeling, however, necessitates the consideration of phenomena beyond the continuum scale. This work presents a comprehensive review on the multiphysics models of lithium-ion, lead-acid, and vanadium redox flow batteries. The electrochemical models of these chemistries are discussed along with their physical interpretations and common applications. Modifications of these multiphysics models for adaptation and matching to end applications are outlined. Lastly, we comment on the direction of future work with regards to the interaction of multiphysics modeling with modeling techniques in other length and time scales. Molecular-scale models such as density functional theory and kinetic Monte Carlo can be used to create new multiphysics models and predict transport property correlations from first principles. Nanostructures and pore-level geometries can be optimized and integrated into continuum-scale models. The reduction of multiphysics models via machine learning, mathematical simplification, or regression enables their application in battery management systems and energy systems modeling.
Catalysts, 2020
The electrooxidation kinetics of ethanol is key to making direct ethanol fuel cells and electroca... more The electrooxidation kinetics of ethanol is key to making direct ethanol fuel cells and electrocatalytically reforming ethanol viable technologies for a more sustainable energy conversion. In this study, the electrooxidation of ethanol was investigated on nickel hydroxide (Ni(OH)2) catalysts synthesized using a facile solvothermal method. Variations in the temperature, heating time, and the addition of oleylamine in the precursor enabled the phase and morphology control of the catalysts. X-ray diffraction and scanning electron microscopy show that the addition of oleylamine in the precursor resulted in microspheres with a high surface area, but favored the formation of β-phase Ni(OH)2. Elevated temperatures or prolonged periods of heating in a controlled environment, on the other hand, can lead to the formation of the ethanol oxidation reaction-active α-phase. Among the synthesized catalysts, the α-Ni(OH)2 microspheres with nanoflakes achieved the highest activity for ethanol oxidat...
Catalysts, 2020
Sluggish kinetics in oxygen reduction reaction (ORR) requires low-cost and highly durable electro... more Sluggish kinetics in oxygen reduction reaction (ORR) requires low-cost and highly durable electrocatalysts ideally produced from facile methods. In this work, we explored the conversion and utilization of waste biomass as potential carbon support for α-MnO2 catalyst in enhancing its ORR performance. Carbon supports were derived from different waste biomass via hydrothermal carbonization (HTC) at different temperature and duration, followed by KOH activation and subsequent heat treatment. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX) and X-Ray diffraction (XRD) were used for morphological, chemical, and structural characterization, which revealed porous and amorphous carbon supports for α-MnO2. Electrochemical studies on ORR activity suggest that carbon-supported α-MnO2 derived from HTC of corncobs at 250 °C for 12 h (CCAC + MnO2 250-12) gives the highest limiting current density and lowest overpotential...
ECS Transactions, 2017
Although platinum and platinum alloys (e.g. PtNi and PtCo) are widely regarded as the best cataly... more Although platinum and platinum alloys (e.g. PtNi and PtCo) are widely regarded as the best catalysts for ORR at present, they are expensive and still suffer from technical drawbacks. Recently, the exploration of Pt-free or even metal-free ORR catalysts including heteroatom-doped carbon nanomaterials is very active in the electrochemistry and carbon research communities. Previous investigations have employed five main dopant elements (i.e. nitrogen, boron, phosporus, sufur, and selenium), with majority of these studies concluding that nitrogen, especially when doped in a specific manner, shows the most positive effect in improving the catalytic activity of carbon. In this study, we explore a new set of dopant atoms (alkali, alkaline earth, and halogen atoms) for the two-dimensional graphene structure (both in the buckled and planar configurations) and look at the changes in the geometric and electronic structures via density functional theory (DFT) calculations. We also qualify and quantify the stability and nature of the substitional doping on graphene and observe the trends for various properties for each elemental group. For instance, the doping of alkaline-earth atoms on the graphene structure, which has been unexplored so far, modifies the electronic properties and consequently the oxygen adsorption energetics. We found that novel properties such as semi-metallic properties emerge after substitutional doping except with beryllium, pointing to the possibility that these doped materials can be used not just in electrochemical but also in catalytic and electronic applications. Figure 1
ECS Transactions, 2017
The electrocatalytic reduction of carbon dioxide (CO2) into hydrocarbons is considered as one of ... more The electrocatalytic reduction of carbon dioxide (CO2) into hydrocarbons is considered as one of the promising solutions to the pressing problems related to energy and climate change as it can reduce atmospheric CO2 concentration and produce carbon-neutral energy. In this work, copper and gold on cabon fiber paper (Cu-Au/CFP) were studied as electrocatalysts for CO2 reduction. The electrocatalysts were synthesized via co-electrodeposition of metal precursors by applying a constant potential on an electrolyte solution containing cupric sulphate pentahydrate, gold (III) chloride trihydrate, and sulfuric acid. The concentration of the gold metal precursor in the electrolyte solution was varied from 5 to 50 mM whereas that of the copper metal precursor was kept constant at 0.40 M. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the morphology and crystallinity of the as-prepared electrocatalysts, respectively. It was determined through SEM that the as-prepared electrocatalysts are made of spherical and porous nanostructures. Fern-like structures were also observed to form when the concentration of the gold metal precursor in the electrolyte solution was increased. XRD analysis showed that Cu (III) dominated all other crystal structures in copper and gold electrocatalysts. The faradaic efficiencies of the electrochemical reduction of CO2 for alcohol and formate of the as-prepared electrocatalysts were found to be considerably higher as compared to that of copper electrode. The insights that are obtained through this study can be a guide for the synthesis of a better catalyst for CO2 electrocatalytic reduction. Figure 1
3rd Annual International Conference on Chemistry, Chemical Engineering and Chemical Process (CCECP 2015), 2015
The Association of Southeast Asian Nations (ASEAN) achieved relatively rapid economic growth over... more The Association of Southeast Asian Nations (ASEAN) achieved relatively rapid economic growth over the past decade. Sustainable growth among member states, however, is put into question due to macroeconomic challenges, political risk, and vulnerability to external shocks. Developed countries, in contrast, have turned into less labor-intensive technologies to further expand their economies. In this paper, we review the science, technology, and innovation (STI) policies and statuses of the scientific and technological capabilities of the ASEAN member countries. Empirical results based on STI indicators (R&D spending, publications, patents, and knowledge economy indices) reveal considerable variation between the science and technology (S&T) competence and effectiveness of STI policies of ASEAN members. We have categorized nations into clusters according their situations in their S&T productivity. Under the Korean Innovation Model, Cambodia, Laos, Myanmar, and Brunei are classified as being in the institutional-building stage, while Malaysia, Thailand, Indonesia, the Philippines, and Vietnam in the catch up stage, and Singapore in the post-catch up stage. Finally, policy prescriptions on how to enhance the S&T capabilities of the developing ASEAN countries, based on the South Korea development experience, are presented.
The Journal of Physical Chemistry C, 2014
Direct ethanol fuel cells (DEFCs) have been widely studied because of their potential as highener... more Direct ethanol fuel cells (DEFCs) have been widely studied because of their potential as highenergy density and low-toxicity power source of the future. Suitable catalysts for the anode reaction, however, are necessary to fully utilize the advantages of DEFCs. In this paper, we fabricated nickel (Ni)-palladium (Pd) bimetallic catalysts with a bilayer structure, using sputtering deposition on a titanium (Ti) foil substrate, and investigated the activity and stability of the catalysts towards ethanol electro-oxidation in alkaline media. Our results suggest that while Pd is the active component and Ni has negligible activity towards ethanol oxidation, Nimodified Pd (NiPd/Ti) provides the best activity in comparison to PdNi/Ti and the monometallic catalysts. In fact, optimizing the Ni amount could lead to a highly active and stable bimetallic electrocatalyst because of Ni's ability to increase the active surface area of the Pd layer, provide hydroxyl species to replenish the active sites, and act as a protective layer to the Pd. Overall, these results provide a better understanding on the role of Ni in bimetallic catalysts, especially in a bilayer configuration, to allow the use of an ethanol oxidation reaction (EOR)-active electrocatalyst with a much lower Pd content.
ASEAN Engineering Journal, 2022
Biofuels are known to have several advantages over fossil fuels including, but not limited to, hi... more Biofuels are known to have several advantages over fossil fuels including, but not limited to, high abundance of resources, negligible SOx emissions, lower NOx emissions, and more environment-friendly processes. In the Philippines, the biofuels industry is anchored onto the Biofuels Act of 2006 which mandates the use of biofuels made from indigenous sources such as coconut. Despite this, biodiesel is still less preferred by consumers over conventional fuel due to its high cost. This can be attributed to high production costs of biodiesel, wherein 18-28% is credited to transportation of products. This work proposes a linear programming model to reduce the overall cost of biodiesel by minimizing the transportation cost in the Philippine biodiesel supply chain, using the Mindanao cluster as case study. Multiple scenarios were done to gauge the impact of varying the supply allocation and biodiesel blend on the supply chain. The optimal supply allocation, transportation cost, and carbon...
ChemistryOpen, 2021
Biodegradable primary batteries, also known as transient batteries, are essential to realize auto... more Biodegradable primary batteries, also known as transient batteries, are essential to realize autonomous biodegradable electronic devices with high performance and advanced functionality. In this work, magnesium, copper, iron, and zinc – metals that exist as trace elements in the human body – were tested as materials for biomedical transient electronic devices. Different full cell combinations of Mg and X (where X = Cu, Fe, and Zn and the anodized form of the metals) with phosphate buffered saline (PBS) as electrolyte were studied. To form the cathodes, metal foils were anodized galvanostatically at a current density of 2.0 mA cm−2 for 30 mins. Electrochemical measurements were then conducted for each electrode combination to evaluate full cell battery performance. Results showed that the Mg−Cuanodized chemistry has the highest power density at 0.99 mW/cm2. Nominal operating voltages of 1.26 V for the first 0.50 h and 0.63 V for the next 3.7 h were observed for Mg−Cuanodized which wa...
Applied Catalysis B: Environmental, 2021
RSC Advances, 2021
Alkaline earth atom dopants on graphene induce work function tuning and spin polarized electronic... more Alkaline earth atom dopants on graphene induce work function tuning and spin polarized electronic properties by ionic bonding.
Journal of Energy Storage, 2021
Abstract The increasing demand for batteries’ application in grid-balancing, electric vehicles, a... more Abstract The increasing demand for batteries’ application in grid-balancing, electric vehicles, and portable electronics has prompted research efforts on improving their performance and safety features. The improvement of batteries involves the comparison of multiple battery designs and the determination of electrochemical and thermal property distributions at the continuum scale. This is achieved by using multiphysics modeling for investigatory battery research, as conventional experimental approaches would be costly and impractical. The fundamental electrochemical models for these batteries have been established, hence, new models are being developed for specific applications, such as thermal runaway and battery degradation in lithium-ion batteries, gas evolution in lead-acid batteries, and vanadium crossover in vanadium redox flow batteries. The inclusion of new concepts in multiphysics modeling, however, necessitates the consideration of phenomena beyond the continuum scale. This work presents a comprehensive review on the multiphysics models of lithium-ion, lead-acid, and vanadium redox flow batteries. The electrochemical models of these chemistries are discussed along with their physical interpretations and common applications. Modifications of these multiphysics models for adaptation and matching to end applications are outlined. Lastly, we comment on the direction of future work with regards to the interaction of multiphysics modeling with modeling techniques in other length and time scales. Molecular-scale models such as density functional theory and kinetic Monte Carlo can be used to create new multiphysics models and predict transport property correlations from first principles. Nanostructures and pore-level geometries can be optimized and integrated into continuum-scale models. The reduction of multiphysics models via machine learning, mathematical simplification, or regression enables their application in battery management systems and energy systems modeling.
Catalysts, 2020
The electrooxidation kinetics of ethanol is key to making direct ethanol fuel cells and electroca... more The electrooxidation kinetics of ethanol is key to making direct ethanol fuel cells and electrocatalytically reforming ethanol viable technologies for a more sustainable energy conversion. In this study, the electrooxidation of ethanol was investigated on nickel hydroxide (Ni(OH)2) catalysts synthesized using a facile solvothermal method. Variations in the temperature, heating time, and the addition of oleylamine in the precursor enabled the phase and morphology control of the catalysts. X-ray diffraction and scanning electron microscopy show that the addition of oleylamine in the precursor resulted in microspheres with a high surface area, but favored the formation of β-phase Ni(OH)2. Elevated temperatures or prolonged periods of heating in a controlled environment, on the other hand, can lead to the formation of the ethanol oxidation reaction-active α-phase. Among the synthesized catalysts, the α-Ni(OH)2 microspheres with nanoflakes achieved the highest activity for ethanol oxidat...
Catalysts, 2020
Sluggish kinetics in oxygen reduction reaction (ORR) requires low-cost and highly durable electro... more Sluggish kinetics in oxygen reduction reaction (ORR) requires low-cost and highly durable electrocatalysts ideally produced from facile methods. In this work, we explored the conversion and utilization of waste biomass as potential carbon support for α-MnO2 catalyst in enhancing its ORR performance. Carbon supports were derived from different waste biomass via hydrothermal carbonization (HTC) at different temperature and duration, followed by KOH activation and subsequent heat treatment. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive X-ray spectroscopy (EDX) and X-Ray diffraction (XRD) were used for morphological, chemical, and structural characterization, which revealed porous and amorphous carbon supports for α-MnO2. Electrochemical studies on ORR activity suggest that carbon-supported α-MnO2 derived from HTC of corncobs at 250 °C for 12 h (CCAC + MnO2 250-12) gives the highest limiting current density and lowest overpotential...
ECS Transactions, 2017
Although platinum and platinum alloys (e.g. PtNi and PtCo) are widely regarded as the best cataly... more Although platinum and platinum alloys (e.g. PtNi and PtCo) are widely regarded as the best catalysts for ORR at present, they are expensive and still suffer from technical drawbacks. Recently, the exploration of Pt-free or even metal-free ORR catalysts including heteroatom-doped carbon nanomaterials is very active in the electrochemistry and carbon research communities. Previous investigations have employed five main dopant elements (i.e. nitrogen, boron, phosporus, sufur, and selenium), with majority of these studies concluding that nitrogen, especially when doped in a specific manner, shows the most positive effect in improving the catalytic activity of carbon. In this study, we explore a new set of dopant atoms (alkali, alkaline earth, and halogen atoms) for the two-dimensional graphene structure (both in the buckled and planar configurations) and look at the changes in the geometric and electronic structures via density functional theory (DFT) calculations. We also qualify and quantify the stability and nature of the substitional doping on graphene and observe the trends for various properties for each elemental group. For instance, the doping of alkaline-earth atoms on the graphene structure, which has been unexplored so far, modifies the electronic properties and consequently the oxygen adsorption energetics. We found that novel properties such as semi-metallic properties emerge after substitutional doping except with beryllium, pointing to the possibility that these doped materials can be used not just in electrochemical but also in catalytic and electronic applications. Figure 1
ECS Transactions, 2017
The electrocatalytic reduction of carbon dioxide (CO2) into hydrocarbons is considered as one of ... more The electrocatalytic reduction of carbon dioxide (CO2) into hydrocarbons is considered as one of the promising solutions to the pressing problems related to energy and climate change as it can reduce atmospheric CO2 concentration and produce carbon-neutral energy. In this work, copper and gold on cabon fiber paper (Cu-Au/CFP) were studied as electrocatalysts for CO2 reduction. The electrocatalysts were synthesized via co-electrodeposition of metal precursors by applying a constant potential on an electrolyte solution containing cupric sulphate pentahydrate, gold (III) chloride trihydrate, and sulfuric acid. The concentration of the gold metal precursor in the electrolyte solution was varied from 5 to 50 mM whereas that of the copper metal precursor was kept constant at 0.40 M. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to characterize the morphology and crystallinity of the as-prepared electrocatalysts, respectively. It was determined through SEM that the as-prepared electrocatalysts are made of spherical and porous nanostructures. Fern-like structures were also observed to form when the concentration of the gold metal precursor in the electrolyte solution was increased. XRD analysis showed that Cu (III) dominated all other crystal structures in copper and gold electrocatalysts. The faradaic efficiencies of the electrochemical reduction of CO2 for alcohol and formate of the as-prepared electrocatalysts were found to be considerably higher as compared to that of copper electrode. The insights that are obtained through this study can be a guide for the synthesis of a better catalyst for CO2 electrocatalytic reduction. Figure 1
3rd Annual International Conference on Chemistry, Chemical Engineering and Chemical Process (CCECP 2015), 2015
The Association of Southeast Asian Nations (ASEAN) achieved relatively rapid economic growth over... more The Association of Southeast Asian Nations (ASEAN) achieved relatively rapid economic growth over the past decade. Sustainable growth among member states, however, is put into question due to macroeconomic challenges, political risk, and vulnerability to external shocks. Developed countries, in contrast, have turned into less labor-intensive technologies to further expand their economies. In this paper, we review the science, technology, and innovation (STI) policies and statuses of the scientific and technological capabilities of the ASEAN member countries. Empirical results based on STI indicators (R&D spending, publications, patents, and knowledge economy indices) reveal considerable variation between the science and technology (S&T) competence and effectiveness of STI policies of ASEAN members. We have categorized nations into clusters according their situations in their S&T productivity. Under the Korean Innovation Model, Cambodia, Laos, Myanmar, and Brunei are classified as being in the institutional-building stage, while Malaysia, Thailand, Indonesia, the Philippines, and Vietnam in the catch up stage, and Singapore in the post-catch up stage. Finally, policy prescriptions on how to enhance the S&T capabilities of the developing ASEAN countries, based on the South Korea development experience, are presented.
The Journal of Physical Chemistry C, 2014
Direct ethanol fuel cells (DEFCs) have been widely studied because of their potential as highener... more Direct ethanol fuel cells (DEFCs) have been widely studied because of their potential as highenergy density and low-toxicity power source of the future. Suitable catalysts for the anode reaction, however, are necessary to fully utilize the advantages of DEFCs. In this paper, we fabricated nickel (Ni)-palladium (Pd) bimetallic catalysts with a bilayer structure, using sputtering deposition on a titanium (Ti) foil substrate, and investigated the activity and stability of the catalysts towards ethanol electro-oxidation in alkaline media. Our results suggest that while Pd is the active component and Ni has negligible activity towards ethanol oxidation, Nimodified Pd (NiPd/Ti) provides the best activity in comparison to PdNi/Ti and the monometallic catalysts. In fact, optimizing the Ni amount could lead to a highly active and stable bimetallic electrocatalyst because of Ni's ability to increase the active surface area of the Pd layer, provide hydroxyl species to replenish the active sites, and act as a protective layer to the Pd. Overall, these results provide a better understanding on the role of Ni in bimetallic catalysts, especially in a bilayer configuration, to allow the use of an ethanol oxidation reaction (EOR)-active electrocatalyst with a much lower Pd content.
ASEAN Engineering Journal, 2022
Biofuels are known to have several advantages over fossil fuels including, but not limited to, hi... more Biofuels are known to have several advantages over fossil fuels including, but not limited to, high abundance of resources, negligible SOx emissions, lower NOx emissions, and more environment-friendly processes. In the Philippines, the biofuels industry is anchored onto the Biofuels Act of 2006 which mandates the use of biofuels made from indigenous sources such as coconut. Despite this, biodiesel is still less preferred by consumers over conventional fuel due to its high cost. This can be attributed to high production costs of biodiesel, wherein 18-28% is credited to transportation of products. This work proposes a linear programming model to reduce the overall cost of biodiesel by minimizing the transportation cost in the Philippine biodiesel supply chain, using the Mindanao cluster as case study. Multiple scenarios were done to gauge the impact of varying the supply allocation and biodiesel blend on the supply chain. The optimal supply allocation, transportation cost, and carbon...
ChemistryOpen, 2021
Biodegradable primary batteries, also known as transient batteries, are essential to realize auto... more Biodegradable primary batteries, also known as transient batteries, are essential to realize autonomous biodegradable electronic devices with high performance and advanced functionality. In this work, magnesium, copper, iron, and zinc – metals that exist as trace elements in the human body – were tested as materials for biomedical transient electronic devices. Different full cell combinations of Mg and X (where X = Cu, Fe, and Zn and the anodized form of the metals) with phosphate buffered saline (PBS) as electrolyte were studied. To form the cathodes, metal foils were anodized galvanostatically at a current density of 2.0 mA cm−2 for 30 mins. Electrochemical measurements were then conducted for each electrode combination to evaluate full cell battery performance. Results showed that the Mg−Cuanodized chemistry has the highest power density at 0.99 mW/cm2. Nominal operating voltages of 1.26 V for the first 0.50 h and 0.63 V for the next 3.7 h were observed for Mg−Cuanodized which wa...