Monodispersed PtPdNi Trimetallic Nanoparticles-Integrated Reduced Graphene Oxide Hybrid Platform for Direct Alcohol Fuel Cell

The direct alcohol fuel cell has recently emerged as an important energy conversion device. In the present article, superior alcohol (ethanol, ethylene glycol, and glycerol) electrooxidation performance using trimetallic platinum–palladium–nickel (PtPdNi) alloy nanoparticles of diameters from 2–4 nm supported on a reduced graphene oxide (rGO) electrocatalyst is demonstrated. A simple and single-step solvothermal technique is adopted to fabricate the alloy/rGO hybrid electrocatalysts by simultaneous reduction of metal ions and graphene oxide. The detailed electrochemical investigation revealed that the performance of the trimetallic/rGO hybrid toward electrooxidation of different alcohols is higher than that of bimetallic alloy/rGO hybrids and the state-of-the-art Pt/C catalyst. The incorporation of Ni into the PtPd alloy is found to change the surface of the electronic structure PtPd alloy leading to higher electrochemical surface areas and improved kinetics. In addition, the hydrophilic nature of Ni not only facilitates alcohol electrooxidation but also electrooxidation of residual carbon impurities formed on the catalyst surface, thus reducing catalyst poisoning, demonstrating its role in the development of anode catalysts for the alcohol fuel cells

Controlled Synthesis of CuS/TiO₂ Heterostructured Nanocomposites for Enhanced Photocatalytic Hydrogen Generation through Water Splitting

Photocatalytic hydrogen (H2) generation through water splitting has attracted substantial attention as a clean and renewable energy generation process that has enormous potential in converting solar-to-chemical energy using suitable photocatalysts. The major bottleneck in the development of semiconductor-based photocatalysts lies in poor light absorption and fast recombination of photogenerated electron–hole pairs. Herein we report the synthesis of CuS/TiO2 heterostructured nanocomposites with varied TiO2 contents via simple hydrothermal and solution-based process. The morphology, crystal structure, composition, and optical properties of the as-synthesized CuS/TiO2 hybrids are evaluated in detail. Controlling the CuS/TiO2 ratio to an optimum value leads to the highest photocatalytic H2 production rate of 1262 μmol h–1 g–1, which is 9.7 and 9.3 times higher than that of pristine TiO2 nanospindles and CuS nanoflakes under irradiation, respectively. The enhancement in the H2 evolution rate is attributed to increased light absorption and efficient charge separation with an optimum CuS coverage on TiO2. The photoluminescence and photoelectrochemical measurements further confirm the efficient separation of charge carriers in the CuS/TiO2 hybrid. The mechanism and synergistic role of CuS and TiO2 semiconductors for enhanced photoactivity is further delineated

Double-Metal-Ion-Exchanged Mesoporous Zeolite as an Efficient Electrocatalyst for Alkaline Water Oxidation: Synergy between Ni–Cu and Their Contents in Catalytic Activity Enhancement

The kinetics of total water splitting is mostly hampered by the sluggish oxygen evolution reaction (OER) at the anode of the electrolyzer. Herein, we focus on the design of a cost-effective porous OER catalyst for efficient water to fuel conversion. A simple metal-ion-exchange protocol is adapted to implant electroactive metal centers in the mesoporous architecture of Zeolite Socony Mobil-5 (ZSM-5). OER-active Ni is incorporated as catalytic sites in the mesoporous ZSM-5. Further, simultaneous incorporation of both Ni²⁺ and Cu²⁺ into the mesoporous ZSM-5 (Meso-Z) matrix significantly boost the OER catalytic activity. The optimization of Ni and Cu contents (1.04 wt % Ni and 0.44 wt % Cu) in the catalyst is found to be essential to achieve high catalytic activity. The Cu content influences the onset potential, and the Ni content determines the catalytic current during OER. Among developed catalysts, Ni₂Cu₁-Meso-Z offers the best performance even better than the state-of-art OER catalyst IrO₂. Ni₂Cu₁-Meso-Z delivers a current density of 10 mA/cm² at an overpotential of 407 mV and exhibits a low Tafel slope of 55 mV/dec, a high electrochemical active surface area of 6.26, and a roughness factor of 89.42. Moreover, Ni₂Cu₁-Meso-Z retains 92% of its initial current density after 1000 potential cycles of a test run. The best performing Ni₂Cu₁-Meso-Z offers a faradic efficiency of 92%, whereas the state-of-the-art IrO₂ efficiency was decreased by 22% under the similar experimental condition. Further, Ni₂Cu₁-Meso-Z-modified anode exhibits better performance in its single cell than IrO₂, in which Pt is used as cathode. The excellent OER catalytic activity of double-metal-ion-exchanged Meso-Z is attributed to the large surface area of mesoporous ZSM-5, hydrophilicity, fast diffusion of water molecules through the favorable interaction with Si–OH groups, and optimum binding and dissociation of different oxygeneous OER intermediates on the catalyst surface. Excellent current density and sustainable performance suggest that the double-metal-ion-exchanged mesoporous zeolite can serve as a potential candidate to improve the overall water splitting in the electrolyzer