Single atom catalysts for boosting electrocatalytic and photoelectrocatalytic performances

Abstract

Electrocatalytic (EC) and photoelectrocatalytic (PEC) water splitting are effective processes for mass production of hydrogen; however, they usually endure large overpotentials or low conversion efficiency. Therefore, the exploration of efficient and scale-up feasible electrocatalysts and cocatalysts is highly desirable. The novel and emerging single Pt atom catalyst is promising to perfectly satisfy the strict requirements of the EC and PEC hydrogen evolution reaction (HER). Herein, a partial nitridation modification strategy is proposed to anchor single platinum (Pt) atoms through the coordination of lone pair electrons of nitrogen atoms with the unoccupied d orbital electrons of Pt atoms. The fixed single Pt atoms are located on a porous nickel framework on nickel foam (Pt₁/N–Ni/NF), and show excellent EC activity with a low overpotential of 33 mV at −10 mA cm⁻² for the HER in neutral solution, which is superior to that of the bench-mark commercial electrocatalyst. In addition, the Pt₁/N–Ni has been integrated into a Cu₂O nanowire photocathode as a cocatalyst, and presents a high photocurrent density of −11.9 mA cm⁻² at 0 V vs. RHE and PEC conversion efficiency of 1.75%. The rational design and preparation of a single atom catalyst both as an electrocatalyst for EC and a cocatalyst for PEC water splitting opens up a new avenue for boosting EC and PEC water splitting performance.