Modulation in d band center of metallic Rh for robust hydrogen evolution reaction.

It is generally known that the hydrogen binding strength with active site guarantees the intrinsic catalytic performance toward hydrogen evolution reaction (HER). A moderate binding strength is requirable to achieve a robust HER electrocatalyst. In this work, we report a facile methodology to balance the hydrogen adsorption/desorption capability of metallic Rh by downshift in d band center via a partial sulfurization to construct Rh–Rh 2 S 3 heterostructure. The downshift in d band center of Rh results in weakening the overly strong hydrogen adsorption to a balanced level. Thereby, Rh–Rh 2 S 3 exhibits large decrements (67.2 mV and 92.2 mV) in overpotential at 100 mA cm−2 in acidic HER catalysis than Rh and Rh 2 S 3. Moreover, the merit of modulation in d band center is also reflected by alkaline HER. The overpotential at 100 mA cm−2 for Rh–Rh 2 S 3 is substantially decreased by 117.9 mV and 74.9 mV compared to Rh 2 S 3 and Rh. Additionally, a 3.3-time higher mass activity at −80 mV vs. RHE is achieved for Rh–Rh 2 S 3 with relative to commercial Pt/C. • Rh–Rh 2 S 3 heterostructure is synthesized via partial sulfurization. • Rh–Rh 2 S 3 exhibits a 3.3-time higher HER activity than Pt/C. • d band center of Rh was downshifted by introduction of Rh 2 S 3. [ABSTRACT FROM AUTHOR]