Synergistic effect between platinum single atoms and oxygen vacancy in MoO2 boosting pH-Universal hydrogen evolution reaction at large current density

Single-atomic or cluster-based precious metals provide an effective pathway to minimize the cost of catalysts. However, its stability at large current density is still a major hurdle to satisfy practical requirements for electrocatalytic Hydrogen evolution reaction (HER). Herein, we successfully anchored Pt single atoms (Pt SAs) in the oxygen vacancies (Ovac) of Molybdenum dioxide (MoO2) as advanced HER electrocatalyst. Experimental and theoretical calculations results reveal that the Ovac can not only stabilize Pt SAs, but also modulate the electronic structure of the active site, enabling Pt SAs/MoO2 to exhibit superior HER activity in a wide pH electrolyte at large current density. Especially, the 1.1 wt% Pt SAs/MoO2 deliver ultralow overpotentials (9.3, 14, and 16 mV at 10 mA cm−2) and small Tafel slopes (28.78, 36.86, and 65.18 mV dec-1) in acidic, alkaline, and neutral electrolytes, respectively. Moreover, it displays significantly enhanced mass activity of up to 28, 32, and 56 times compared to the benchmark 20 wt% Pt/C catalyst, and outstanding long-term durability (~200 h) at large current density of −1000 mA cm−2. The significantly improved HER performances are mainly ascribed to the synergistic catalytic effects of between Pt SAs and Ovac in MoO2. These impressive findings can provide insights into the rational design of electrocatalysts that used for future clean energy utilization.