The development of efficient catalytic electrodes towards the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is at the heart of renewable-energy technologies. Despite the tremendous efforts towards engineering electrode schemes for increasing exposed surface areas and active sites, improving intrinsic catalytic activity still remains a great challenge. Here, we develop a surface-polyaniline (PANI) functionalized nickel selenide (NiSe–PANI) electrode with great performance enhancement for both the HER and OER. The decorated PANI layer subtly modulates the surface electronic structures of NiSe, with a surface-optimized selenium-enriched configuration for the HER and enhanced generation of Ni^III/IV active species when oxidized for the OER. When used as a bifunctional electrocatalyst for overall water splitting, the NiSe–PANI electrode displays excellent performance, with a current density of ∼10 mA cm⁻² at an applied voltage of 1.53 V during a long-term electrolysis test, and outperforms the Pt and IrO₂ combination as the benchmark and most of the earth-abundant material-based bifunctional catalysts. Similar PANI–functionalization on other bifunctional nickel chalcogenide electrodes also exhibits obviously enhanced performance for overall water splitting, demonstrating the wider applicability of intrinsic activity enhancement via a surface electronic modulation strategy.

中文翻译：

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硒化镍的表面处理可提高固有的整体水分解能力†

向氢气释放反应（HER）和氧气释放反应（OER）的高效催化电极的开发是可再生能源技术的核心。尽管为增加暴露的表面积和活性位点而对工程电极方案做出了巨大的努力，但是改善固有的催化活性仍然是巨大的挑战。在这里，我们开发了一种表面聚苯胺（PANI）功能化的硒化镍（NiSe–PANI）电极，该电极对HER和OER都有很大的增强作用。装饰的PANI层巧妙地调节了NiSe的表面电子结构，具有用于HER的表面优化的富硒构造，并增强了Ni ^{III / IV的生成}氧化为OER时的活性物质。当用作整体水分解的双功能电催化剂时，NiSe–PANI电极表现出出色的性能，在长期电解测试中，在1.53 V的施加电压下，电流密度为〜10 mA cm ^-2，并且性能优于Pt和IrO ₂组合作为基准，并且是大多数地球上存在的基于材料的双功能催化剂。在其他双功能硫属元素化物镍电极上进行的类似PANI功能化也表现出明显的整体水分解性能，这表明通过表面电子调制策略来增强内在活性具有更广泛的适用性。