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High performance duckweed-derived carbon support to anchor NiFe electrocatalysts for efficient solar energy driven water splitting

Kumar, Ashwani, Chaudhary, Dhirendra K., Parvin, Sahanaz, Bhattacharyya, Sayan
Journal of materials chemistry 2018 v.6 no.39 pp. 18948-18959
Araceae, biomass, bubbles, carbon, catalysts, cost effectiveness, electric potential difference, fuel production, hydrogen, hydrogen production, nanoparticles, oxygen, porous media, potassium hydroxide, solar cells, solar energy
Solar-energy-driven overall water splitting using sustainable energy resources is extremely desirable for high purity hydrogen fuel production, and one of the ways is to couple cost-effective solar cells in series with earth-abundant electrocatalysts for oxygen and hydrogen evolution reactions, OER and HER, respectively. Developing highly efficient and earth-abundant electrocatalysts however remains one of the grand challenges. Herein, we developed biomass (duckweed, DW) derived N,S-doped mesoporous carbon matrix supported NiFe-alloy nanoparticles (NPs) as efficient electrocatalysts for overall water splitting. While the annealed catalyst required 267 mV overpotential at 10 mA cm⁻² for the OER, the best HER performance was demonstrated by the unannealed electrocatalyst requiring 106 mV at −10 mA cm⁻² in 1 M KOH. For overall water splitting, this couple required only 1.61 V cell voltage to deliver 10 mA cm⁻², with continuous release of O₂ and H₂ gas bubbles for more than 200 h. On integrating with perovskite solar cells, the homologous DW electrolyzer exhibited unassisted solar-energy-driven overall water splitting with a solar-to-hydrogen (STH) conversion efficiency of 9.7%.