Highly Efficient and Stable Hydrogen Production in All pH Range by Two-Dimensional Structured Metal-Doped Tungsten Semicarbides
ECSA analysis. Cyclic voltammograms (CVs) of (a) W2C, (b) 2% Fe-W2C, (c) 2% Co-W2C, and (d) 2% Ni-W2C NSs obtained in a potential window of 0.192-0.242 V (vs. RHE) at various scan rates of 5, 10, 20, 50, and 100 mV s−1 in 0.5 M H2SO4 solution. (e) The capacitive current (-) at 0.22 V (vs. RHE) as a function of the scan rate for the W2C and 2% M-W2C (M=Fe, Co, and Ni) NSs. (f) HER polarization curves of W2C, 2% Fe-W2C, 2% Co-W2C, and 2% Ni-W2C NSs after electrochemical active area (ECSA) normalization.