Abstract：
The construction and regulation of built-in electric field (BIEF) are considered effective strategies for enhancing the oxygen evolution reaction (OER) performance of transition metal-based electrocatalysts. Herein, we present a strategy to regulate the electronic structure of nickel-iron layered double hydroxide (NiFe-LDH) by constructing and enhancing the BIEF induced by in-situ heterojunction transformation. This concept is demonstrated through the design and synthesis of Ag2S@S/NiFe-LDH (p-n heterojunction) and Ag@S/NiFe-LDH (Mott-Schottky heterojunction). Benefiting from the larger BIEF of Mott-Schottky heterojunction, efficient electron transfer occurs at the interface between silver (Ag) and NiFe-LDH. As a result, Ag@S/NiFe-LDH exhibits excellent OER performance, requiring only a 232 mV overpotential at 1 M KOH to achieve a current density of 100 mA cm-2, with a small Tafel slope of 73 mV dec-1, as well as excellent electrocatalytic durability. Density functional theory (DFT) calculations further verified that stronger BIEF in Mott-Schottky heterojunction enhances the electron interaction at the interfaces, reduces the energy barrier for the rate-determining step (RDS), and accelerates the OER kinetics. This work provides an effective strategy for designing catalyst with larger BIEF to enhance electrocatalytic activity.
摘要：
内置电场（BIEF）的构建和调节被认为是增强过渡金属基电催化剂析氧反应（OER）性能的有效策略。在这里，我们提出了一种策略，通过构建和增强原位异质结转化诱导的BIEF来调节镍铁层状双氢氧化物（NiFe-LDH）的电子结构。通过Ag2S@S/NiFe-LDH（p-n异质结）和Ag@S/NiFe-LDH（Mott-Schottky异质结）的设计和合成证明了这一概念。受益于Mott-Schottky异质结的较大BIEF，有效的电子转移发生在银(Ag)和NiFe-LDH之间的界面处。因此,Ag@S/NiFe-LDH表现出优异的OER性能，在1MKOH下仅需要232mV的过电位，即可实现100mAcm-2的电流密度，而Tafel的小斜率为73mVdec-1，以及出色的电催化耐久性。密度泛函理论（DFT）计算进一步验证了Mott-Schottky异质结中更强的BIEF增强了界面处的电子相互作用，降低速率确定步骤(RDS)的能量势垒，并加速OER动力学。这项工作为设计具有较大BIEF的催化剂以增强电催化活性提供了有效的策略。
