Unraveling the effect of transition-metal doping on the structural, electronic, and electrocatalytic HER performance of monolayer HfTe 2

. Formation energies under Te-rich conditions are all negative, confirming doping feasibility. Dissolution analysis identifies that Ru balances activity and stability under acidic conditions, while Fe, Co, and Re are susceptible to dissolution, and Ir and Au resist dissolution. This provides guidelines for HER catalyst design.