TY - JOUR AU - Qian, Guangfu AU - Chen, Jinli AU - Yu, Tianqi AU - Liu, Jiacheng AU - Luo, Lin AU - Yin, Shibin PY - 2021/12/09 Y2 - 2024/03/28 TI - Three-Phase Heterojunction NiMo-Based Nano-Needle for Water Splitting at Industrial Alkaline Condition JF - Nano-Micro Letters JA - Nano-Micro Lett VL - 14 IS - SE - Articles DO - 10.1007/s40820-021-00744-x UR - https://nmlett.org/index.php/nml/article/view/1006 SP - 20 AB - <p>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/MoO<sub>2</sub> nano-needle with three-phase heterojunction (Ni/MoO<sub>2</sub>@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 Δ<em>G</em><sub>H*</sub> for hydrogen evolution reaction (HER) and decrease the Δ<em>G</em> value of rate-determining step for oxygen evolution reaction (OER), thus enhancing the HER/OER catalytic activity. Electrochemical results confirm that Ni/MoO<sub>2</sub>@CN exhibits good activity for HER (<em>ƞ</em><sub><em>-</em>10</sub> = 33&nbsp;mV, <em>ƞ</em><sub><em>-</em>1000</sub> = 267&nbsp;mV) and OER (<em>ƞ</em><sub>10</sub> = 250&nbsp;mV, <em>ƞ</em><sub>1000</sub> = 420&nbsp;mV). It shows a low potential of 1.86&nbsp;V at 1000&nbsp;mA&nbsp;cm<sup>−2</sup> for WS in 6.0&nbsp;M KOH solution at 60&nbsp;°C and can steadily operate for 330&nbsp;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.</p><p>Highlights:</p><p>1 Three-phase heterojunction can adjust the ∆G of H/O-intermediates to boost catalytic activity.<br>2 At ± 1000 mA cm<sup>−2</sup>, Ni/MoO<sub>2</sub>@CN exhibits low hydrogen/oxygen evolution reaction overpotentials (267/420 mV).<br>3 Ni/MoO<sub>2</sub>@CN used as bifunctional electrodes can work at 1000 mA cm<sup>−2</sup> for 330 h in 6.0 M KOH + 60 °C condition.</p> ER -