Defect-rich W 1- x Mo x S 2 solutions for efficient H 2 evolution in acidic electrolytes.

An optimal W 0.4 Mo 0.6 S 2 solid solution, equipped with rich intrinsic defects, exhibits excellent stability in both 0.5 M H 2 SO 4 and 2.0 M NaCl, showing negligible activity degradation after continuous 50 hours of working, thereby showing outstanding practical prospects.