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
Sanjib Baran Roy, Sunil Moon, Kwang Hee kim, Amar M. Patil, Malik Abdul Rehman, SangHyuk Yoo, Youngho Seo, Jong Hyeok Park, Keonwook Kang, Seong Chan Jun
Abstract
Efficient water electrolysis requires highly active electrocatalysts with Pt/RuO 2 -like performance, which remain challenging to synthesize. To develop an ideal universal-pH catalyst, we fabricated N-doped noble metal iridium diphosphide (N-IrP 2 @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 H 2 SO 4 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 IrP 2 surface. Thus, a highly efficient and robust catalyst was developed for commercial water electrolysis.