Greenly Reduced CoFe-PBA/Nickel Foam: A Robust Dual Electrocatalyst for Solar-Driven Alkaline Water Electrolysis with a Low Cell Voltage

Development of eco-friendly efficient dual electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) gaining increased attention for renewable energy production. Here, the greenly synthesized rCoFe-PBA was established as durable and effective bifunctional electrocatalyst for HER and OER process. The rCoFe-PBA coated Nickel foam electrode exhibit overpotential of 311 mV (OER) and 100 mV (HER) @ 10 mA cm(-2) significantly lower than commercial IrO2 (381 mV) and near to Pt/C (36 mV). The rCoFe-PBA show smaller Tafel slope (OER: 57 mV dec(-1)) than IrO2 (78 mV dec(-1)) and exhibit Tafel slope of 131 mV dec(-1) (HER) which is near to Pt (90 mV dec(-1)). Turnover frequency (TOF) was estimated as 0.22 s(-1) (OER) and 0.26 s(-1) (HER) was found to be 5 and 10 times higher than IrO2 catalyst (0.040 s(-1)) and Pt/C catalyst (0.025 s(-1)), respectively. For solar water electrolysis, rCoFe-PBA/NF shows overpotential of 411 mV and durability over 180 h in 1.0 m KOH (4.1 % potential loss). The combination of non-precious electrolyzer, rCoFe-PBA with commercial solar cell produced H-2 gas in alkaline water under sunlight. This methodology proves that the greenly synthesized rCoFe-PBA electrolyzer can outperform the precious electrocatalysts, implying that the cost-effective large scale H-2 production without artificial current is possible with commercial solar cells.