Joseph Cline - Academia.edu (original) (raw)
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Papers by Joseph Cline
ACS Applied Nano Materials, 2022
ACS Applied Materials & Interfaces, 2020
Nanocomposite photocatalysts offer a promising route to efficient and clean hydrogen production. ... more Nanocomposite photocatalysts offer a promising route to efficient and clean hydrogen production. However, the multi-step, high temperature, solvent based syntheses typically utilized to prepare these photocatalysts can limit their scalability and sustainability. Bio-synthetic routes to produce functional nanomaterials occur at room temperature and in aqueous conditions, but typically do not produce high-performance materials. We have developed a method to produce a highly efficient hydrogen evolution photocatalyst consisting of CdS quantum dots (QDs) supported on reduced graphene oxide (rGO) via enzyme-based syntheses combined with tuned ligand exchange mediated self-assembly. All preparation steps are carried out in an aqueous environment at ambient temperature. Size-controlled CdS QDs and rGO are prepared through enzyme-mediated turnover of L-cysteine to HSin aqueous solutions of Cd-acetate and graphene oxide, respectively. Exchange of cysteamine for the native Lcysteine ligand capping the CdS QDs, drives self-assembly of the now positively charged cysteamine-capped CdS (CdS/CA) onto negatively charged rGO. The use of this short linker molecule additionally enables efficient charge transfer from CdS to rGO, increasing exciton lifetime and, subsequently, photocatalytic activity. The visible light hydrogen evolution rate of the resulting CdS/CA/rGO photocatalyst is 3300 μmol hr-1 g-1. This represents, to our knowledge, one of the highest reported rates for a CdS/rGO nanocomposite photocatalyst, irrespective of synthesis method.
ACS Applied Materials & Interfaces, 2019
CuZnSnS (CZTS) quantum dots (QDs) have potential application in quantum dot sensitized solar cell... more CuZnSnS (CZTS) quantum dots (QDs) have potential application in quantum dot sensitized solar cells (QDSSCs); however, traditional synthesis approaches typically require elevated temperatures, expensive precursors, and organic solvents that can hinder large scale application. Herein we develop and utilize an enzymatic, aqueous phase, ambient temperature route to prepare CZTS nanocrystals with good compositional control. Nanoparticle synthesis occurs in a minimal buffered solution containing only the enzyme, metal chloride and acetate salts, and L-cysteine as a capping agent and sulfur source. Beyond isolated nanocrystal synthesis, we further demonstrate biomineralization of these particles within a preformed mesoporous TiO 2 anode template where the formed nanocrystals bind to the TiO 2 surface. This in-situ biomineralization approach facilitates enhanced distribution of the nanocrystals in the anode and, through this, enhanced QDSSC performance.
physica status solidi (RRL) - Rapid Research Letters, 2016
The CuNi binary alloy can be significant as a catalyst for nitrogen‐doped (N‐doped) graphene grow... more The CuNi binary alloy can be significant as a catalyst for nitrogen‐doped (N‐doped) graphene growth considering controllable solubility of both carbon and nitrogen atoms. Here, we report for the first time the possibility of synthesizing substitutional N‐doped bilayer graphene on the binary alloy catalyst. Raman spectroscopy, atomic force microscopy and transmission electron microscopy analysis confirm the growth of bilayer and few‐layer graphene domains. X‐ray photoelectron spectroscopy analysis shows the presence of around 5.8 at% of nitrogen. Our finding shows that large N‐doped bilayer graphene domains can be synthesized on the CuNi binary alloy.
Nanoscale, 2018
Traditional quantum dot synthesis techniques rely on the separation of nucleation and growth to c... more Traditional quantum dot synthesis techniques rely on the separation of nucleation and growth to control nanocrystal size. Herein we demonstrate that similar control can be achieved through the continuous generation of reactive precursors throughout synthesis.
ACS Applied Nano Materials, 2022
ACS Applied Materials & Interfaces, 2020
Nanocomposite photocatalysts offer a promising route to efficient and clean hydrogen production. ... more Nanocomposite photocatalysts offer a promising route to efficient and clean hydrogen production. However, the multi-step, high temperature, solvent based syntheses typically utilized to prepare these photocatalysts can limit their scalability and sustainability. Bio-synthetic routes to produce functional nanomaterials occur at room temperature and in aqueous conditions, but typically do not produce high-performance materials. We have developed a method to produce a highly efficient hydrogen evolution photocatalyst consisting of CdS quantum dots (QDs) supported on reduced graphene oxide (rGO) via enzyme-based syntheses combined with tuned ligand exchange mediated self-assembly. All preparation steps are carried out in an aqueous environment at ambient temperature. Size-controlled CdS QDs and rGO are prepared through enzyme-mediated turnover of L-cysteine to HSin aqueous solutions of Cd-acetate and graphene oxide, respectively. Exchange of cysteamine for the native Lcysteine ligand capping the CdS QDs, drives self-assembly of the now positively charged cysteamine-capped CdS (CdS/CA) onto negatively charged rGO. The use of this short linker molecule additionally enables efficient charge transfer from CdS to rGO, increasing exciton lifetime and, subsequently, photocatalytic activity. The visible light hydrogen evolution rate of the resulting CdS/CA/rGO photocatalyst is 3300 μmol hr-1 g-1. This represents, to our knowledge, one of the highest reported rates for a CdS/rGO nanocomposite photocatalyst, irrespective of synthesis method.
ACS Applied Materials & Interfaces, 2019
CuZnSnS (CZTS) quantum dots (QDs) have potential application in quantum dot sensitized solar cell... more CuZnSnS (CZTS) quantum dots (QDs) have potential application in quantum dot sensitized solar cells (QDSSCs); however, traditional synthesis approaches typically require elevated temperatures, expensive precursors, and organic solvents that can hinder large scale application. Herein we develop and utilize an enzymatic, aqueous phase, ambient temperature route to prepare CZTS nanocrystals with good compositional control. Nanoparticle synthesis occurs in a minimal buffered solution containing only the enzyme, metal chloride and acetate salts, and L-cysteine as a capping agent and sulfur source. Beyond isolated nanocrystal synthesis, we further demonstrate biomineralization of these particles within a preformed mesoporous TiO 2 anode template where the formed nanocrystals bind to the TiO 2 surface. This in-situ biomineralization approach facilitates enhanced distribution of the nanocrystals in the anode and, through this, enhanced QDSSC performance.
physica status solidi (RRL) - Rapid Research Letters, 2016
The CuNi binary alloy can be significant as a catalyst for nitrogen‐doped (N‐doped) graphene grow... more The CuNi binary alloy can be significant as a catalyst for nitrogen‐doped (N‐doped) graphene growth considering controllable solubility of both carbon and nitrogen atoms. Here, we report for the first time the possibility of synthesizing substitutional N‐doped bilayer graphene on the binary alloy catalyst. Raman spectroscopy, atomic force microscopy and transmission electron microscopy analysis confirm the growth of bilayer and few‐layer graphene domains. X‐ray photoelectron spectroscopy analysis shows the presence of around 5.8 at% of nitrogen. Our finding shows that large N‐doped bilayer graphene domains can be synthesized on the CuNi binary alloy.
Nanoscale, 2018
Traditional quantum dot synthesis techniques rely on the separation of nucleation and growth to c... more Traditional quantum dot synthesis techniques rely on the separation of nucleation and growth to control nanocrystal size. Herein we demonstrate that similar control can be achieved through the continuous generation of reactive precursors throughout synthesis.