Cobalt supported on biomass carbon tubes derived from cotton fibers towards high-efficient electrocatalytic overall water-splitting

Biomass-derived carbon supported cobalt-phospho-boride as a bifunctional electrocatalyst for enhanced alkaline water splitting

Developing efficient and low-cost bifunctional electrocatalysts for overall water splitting in order to reduce the future energy crisis is crucial and challenging. Herein, a facile two-step fabrication via pyrolysis and chemical reduction was used for the synthesis of biomass-derived carbon-based electrocatalyst (MT) from mulberry bark and its subsequent modification with cobalt phospho-boride (MT/CoPB) for efficient bifunctional electrocatalysis in alkaline media. The effect of B/P ratios and carbon-to-metal ratios on electrocatalytic performance of HER was investigated. Notably, the optimized MT/CoPB catalyst (B/P = 5, C : M = 2 : 1) exhibited a lower overpotential of -86 mV for HER and 310 mV for OER to reach the current density of 10 mA cm-2. The robust electrocatalytic performance of MT/CoPB towards the HER and OER was attributed to the combined effect of carbon and CoPB. Notably, it achieved a low cell voltage of 1.59 V to reach a current density of 10 mA cm-2, also maintaining reliable long-term stability. Characterization studies revealed that the enhanced performance was due to the amorphous structure of the catalyst, high electrochemical surface area, and efficient charge transfer. This work demonstrates the potential of biomass-derived carbon-based materials in the development of cost-effective and durable electrocatalysts for water splitting and green hydrogen production.

Waste-Derived Catalysts for Water Electrolysis: Circular Economy-Driven Sustainable Green Hydrogen Energy

The sustainable production of green hydrogen via water electrolysis necessitates cost-effective electrocatalysts. By following the circular economy principle, the utilization of waste-derived catalysts significantly promotes the sustainable development of green hydrogen energy. Currently, diverse waste-derived catalysts have exhibited excellent catalytic performance toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall water electrolysis (OWE). Herein, we systematically examine recent achievements in waste-derived electrocatalysts for water electrolysis. The general principles of water electrolysis and design principles of efficient electrocatalysts are discussed, followed by the illustration of current strategies for transforming wastes into electrocatalysts. Then, applications of waste-derived catalysts (i.e., carbon-based catalysts, transitional metal-based catalysts, and carbon-based heterostructure catalysts) in HER, OER, and OWE are reviewed successively. An emphasis is put on correlating the catalysts' structure-performance relationship. Also, challenges and research directions in this booming field are finally highlighted. This review would provide useful insights into the design, synthesis, and applications of waste-derived electrocatalysts, and thus accelerate the development of the circular economy-driven green hydrogen energy scheme.