Efficient and bifunctional nonprecious catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are essential for the production of green hydrogen via water electrolysis. Transition metal (Ni, Co, Fe, etc.) phosphides are frequently documented HER catalysts, whereas their bimetallic oxides are efficient OER catalysts, thus enabling bifunctional catalysis for water electrolysis via proper operation. Herein, phosphide-reduced graphene oxide (rGO) hybrids were prepared from graphene oxide (GO)-incorporated bimetal Prussian blue analog (PBA) precursors. The hybrids could experience partial surface oxidation to create oxide layers with OER activities, and the hybrids also possessed considerable HER properties, therefore enabling bifunctional catalytic features for water electrolysis. The typical NiFeP-rGO hybrid demonstrated an overpotential of 250 mV at 10 mA cm-2 and good durability for OER, as well as moderate HER catalytic features (overpotential of 165 mV at -10 mA cm-2 and acceptable catalytic stability). Due to the bifunctional catalytic features, the NiFeP-rGO-based symmetric water electrolyzer demonstrated a moderate input voltage and high faradaic efficiency (FE) for O2 and H2 production. The current work provides a feasible way to prepare OER and HER bifunctional catalysts by facile phosphorization of PBA-associated precursors and spontaneous surface oxidation. Given the oxidation/reduction bifunctional catalytic behaviors, phosphide-rGO hybrid catalysts have great potential for widespread application in fields beyond water electrolysis, such as electrochemical pollution abatement, sensors, energy devices and organic syntheses.

中文翻译：

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普鲁士蓝类似物衍生的镍铁磷化物-还原氧化石墨烯杂化物作为整体水电解的有效催化剂。

用于析氧反应 (OER) 和析氢反应 (HER) 的高效双功能非贵金属催化剂对于通过电解水生产绿色氢气至关重要。过渡金属（Ni、Co、Fe 等）磷化物经常被记录为 HER 催化剂，而它们的双金属氧化物是有效的 OER 催化剂，因此可以通过适当的操作实现水电解的双功能催化。在此，磷化物还原的氧化石墨烯（rGO）杂化物由氧化石墨烯（GO）结合的双金属普鲁士蓝类似物（PBA）前体制备。杂化物可以经历部分表面氧化以产生具有 OER 活性的氧化物层，并且杂化物还具有相当大的 HER 特性，因此能够实现水电解的双功能催化特性。典型的 NiFeP-rGO 杂化物在 10 mA cm-2 时表现出 250 mV 的过电势和良好的 OER 耐久性，以及适度的 HER 催化特性（-10 mA cm-2 时 165 mV 的过电势和可接受的催化稳定性）。由于双功能催化特性，基于 NiFeP-rGO 的对称水电解槽在 O2 和 H2 生产中表现出适中的输入电压和高法拉第效率 (FE)。目前的工作提供了一种可行的方法，通过 PBA 相关前体的轻松磷酸化和自发表面氧化来制备 OER 和 HER 双功能催化剂。鉴于氧化/还原双功能催化行为，磷化物-rGO杂化催化剂在水电解以外的领域具有广泛应用的巨大潜力，例如电化学污染治理，传感器，