One-Step Approach for Constructing High-Density Single-Atom Catalysts toward Overall Water Splitting at Industrial Current Densities.

The construction of highly active, durable, and cost-effective catalysts is urgently needed for green hydrogen production. Herein, catalysts consisting of high-density Pt (24 atoms nm ) and Ir (32 atoms nm ) single atoms anchored on Co(OH) were constructed by a facile one-step approach. Remarkably, Pt /Co(OH) and Ir /Co(OH) only required 4 and 178 mV at 10 mA cm for hydrogen evolution reaction and oxygen evolution reaction, respectively. Moreover, the assembled Pt /Co(OH) //Ir /Co(OH) system showed mass activity of 4.9 A mg at 2.0 V in an alkaline water electrolyzer, which is 316.1 times higher than that of Pt/C//IrO . Mechanistic studies revealed that reconstructed Ir-O single atoms and remodeled Pt triple-atom sites enhanced the occupancy of Ir-O bonding orbitals and improved the occupation of Pt-H antibonding orbital, respectively, contributing to the formation of the O-O bond and the desorption of hydrogen. This one-step approach was also generalized to fabricate other 20 single-atom catalysts.