Amorphous Co-W-P grown on carbon cloth as a bifunctional catalytic electrode for water splitting

The high-performance catalytic electrodes are always required in industrial water electrolysis for enhancing the efficiency of energy conversion. In this paper, we utilized a simple electroless deposition method to deposit Co-W-P on carbon cloth (CC), to construct a bifunctional Co-W-P/CC self-supported electrode for electrochemical water splitting in 1.0 M KOH. The Co-W-P on CC is amorphous and displays nodular structure. The molar ratio of Co2+/WO42− in the synthesis process makes remarkable influence on the catalytic activity of Co-W-P/CC. For optimized Co-W-P/CC-3 (Co2+/WO42− molar ratio about 6:1), an overpotential of 150 mV at −10 mA·cm−2 is required with a Tafel slope of 137.3 mV·dec−1 toward hydrogen evolution reaction (HER), and an overpotential of 350 mV at 10 mA·cm−2 is required with a Tafel slope of 113.2 mV·dec−1 toward oxygen evolution reaction (OER). Furthermore, when functioned as a bifunctional electrode for overall water splitting, the electrolyzer of Co-W-P/CC (−)//Co-W-P/CC (+) shows the cell voltage of 1.74 V at 10 mA·cm−2, as well as superior stability with negligible increase of cell voltage (0.05 V) over 20 h. The work provides an efficient and inexpensive electrode material, which can be used to replace the noble metal-based catalysts for electrochemical water splitting.