Tuning the band (p and d) center and enhancing the active sites by nitrogen (N) doping on iridium diphosphide (IrP2) for accelerating pH-universal water electrolysis

Efficient water electrolysis requires highly active electrocatalysts with Pt/RuO2-like performance, which remain challenging to synthesize. To develop an ideal universal-pH catalyst, we fabricated N-doped noble metal iridium diphosphide (N-IrP2 @CC) catalyst via three-step synthesis on a carbon cloth substrate. The catalyst showed considerably higher catalytic activity compared with existing transition metal phosphide catalysts due to the P-rich condition and N dopants, achieving an overall water-splitting current density of 100 mA cm(-2) at low operation voltages of 1.56 V and 1.64 V in 0.5 M H2SO4 and 1 M KOH, respectively. Density functional theory calculations showed that the N dopant can alter not only the band (d and p) center of Ir and P, but also the charge distribution of the IrP2 surface. Thus, a highly efficient and robust catalyst was developed for commercial water electrolysis.

Automated summary

Developing efficient water electrolysis catalysts remains a challenge. In this study, we synthesized a nitrogen-doped noble metal iridium diphosphide (N-IrP2 @CC) catalyst on a carbon cloth substrate. The catalyst exhibited high catalytic activity due to the phosphorus-rich condition and nitrogen dopants, achieving a high water-splitting current density at low operation voltages.