Constructing heterojunction is an effective strategy to develop high-performance non-precious-metal-based catalysts for electrochemical water splitting (WS). Herein, we design and prepare an N-doped-carbon-encapsulated Ni/MoO2 nano-needle with three-phase heterojunction (Ni/MoO2@CN) for accelerating the WS under industrial alkaline condition. Density functional theory calculations reveal that the electrons are redistributed at the three-phase heterojunction interface, which optimizes the adsorption energy of H- and O-containing intermediates to obtain the best ΔGH* for hydrogen evolution reaction (HER) and decrease the ΔG value of rate-determining step for oxygen evolution reaction (OER), thus enhancing the HER/OER catalytic activity. Electrochemical results confirm that Ni/MoO2@CN exhibits good activity for HER (ƞ-10 = 33 mV, ƞ-1000 = 267 mV) and OER (ƞ10 = 250 mV, ƞ1000 = 420 mV). It shows a low potential of 1.86 V at 1000 mA cm−2 for WS in 6.0 M KOH solution at 60 °C and can steadily operate for 330 h. This good HER/OER performance can be attributed to the three-phase heterojunction with high intrinsic activity and the self-supporting nano-needle with more active sites, faster mass diffusion, and bubbles release. This work provides a unique idea for designing high efficiency catalytic materials for WS.
Developing highly efficient Pt‐based catalysts through interface engineering is significant for hydrogen production by water electrolysis working at pH‐universal conditions but still challenging. Herein, a PtCo@PtSn heterojunction with good hydrogen evolution reaction (HER) performance in pH‐universal electrolytes is designed and prepared by combining the advantages of a Pt‐based bimetallic alloy and heterojunction. Density functional theory simulations illustrate that the surface electronic structure of Pt is optimized by interface engineering to effectively improve the ability of water dissociation and decrease the PtH bond strength for obtaining the suitable H* Gibbs free energy (∆GH*). It shows low HER overpotentials in 1.0 m KOH (η−10 = 25 mV), 1.0 m phosphate‐buffered saline (η−10 = 18 mV), and 0.5 m H2SO4 (η−10 = 21 mV) solutions, respectively, and it can steadily work for 100 000 (100k) cycles by cyclic voltammetry method. Thus, this work provides a novel strategy to design Pt‐based hydrogen evolution catalyst with robust catalytic performance.
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