构筑非晶/晶体NiFe-MOF@NiS异质结构催化剂增强大电流密度下水/海水氧化  

Constructing amorphous/crystalline NiFe-MOF@NiS heterojunction catalysts for enhanced water/seawater oxidation at large current density

作　　者：侯现飚 于辰 倪腾嘉 张树聪 周健 代水星 初蕾[1] 黄明华 Xianbiao Hou;Chen Yu;Tengjia Ni;Shucong Zhang;Jian Zhou;Shuixing Dai;Lei Chu;Minghua Huang(School of Materials Science and Engineering,Ocean University of China,Qingdao 266100,Shandong,China)

机构地区：[1]中国海洋大学材料科学与工程学院,山东青岛266100

出　　处：《Chinese Journal of Catalysis》2024年第6期192-204,共13页催化学报（英文）

基　　金：国家自然科学基金(52261145700,22279124);山东省自然科学基金(ZR2022ZD30);青岛新能源山东实验室开放项目(QNESL OP202307);中央高校基本科研业务费(202262010).

摘　　要：电化学水分解作为一种生产高纯度氢气的绿色技术,虽然前景广阔,但阳极析氧反应(OER)动力学缓慢,严重制约了其能量转换效率.目前,电化学水分解系统主要以淡水作为原料.然而,大规模使用淡水进行分解无疑会给淡水资源带来沉重负担.相比之下,占水资源总量96%以上的海水,因其丰富的储量,成为替代淡水的理想选择.然而,由于海水中含有大量的氯离子,会引发与OER的竞争性氯析出反应(ClER)形成次氯酸盐(ClO^(–)),导致活性位点失活,严重降低催化剂的活性和稳定性.因此,如何在利用海水进行电化学水分解的同时,有效抑制ClER的发生,是当前亟待解决的科学问题.在最新催化剂研究中,金属有机框架(MOF)凭借其高孔隙率、大比表面积和分散的活性位点,在电化学水分解中展现出良好的性能.然而,MOF的电子导电性和OER反应能垒受限于氧原子p轨道与金属原子d轨道间的电子云重叠.因此,设计MOF活性位点的电子结构,促进自发电子转移,对于提升导电性和OER效率至关重要.界面工程能优化MOF活性位点的电子结构,增强局部电荷再分配,从而提高OER活性.为满足工业高电流密度需求,构建富含缺陷的异质结构是关键,其能暴露更多OER活性位点,优化质量传递,缩短电子迁移路径.结合高导电、可调电子结构的NiS晶体相,构建MOF非晶/NiS晶体异质界面,可调控电子结构并加速电荷转移.目前,关于MOF基非晶/晶异质界面催化剂用于海水氧化的报道尚少,这一方向具有巨大潜力.本文通过两步法耦合策略,成功在泡沫镍基底上制备了NiFe-MOF@NiS异质结构催化剂.首先,利用硫温和改性腐蚀方法在泡沫镍基体生长晶相NiS纳米片;随后,通过电沉积处理在NiS表面生长非晶相NiFe-MOF纳米颗粒.理论计算结果表明,NiFe-MOF和NiS之间的电子相互作用可以加速电荷转移,有效调节金属位点的d带中心,从而优化含氧中�Developing metal-organic frameworks(MOF)based catalysts with high activity and chlorine corrosion resistance is of paramount importance for seawater oxidation at large current density.Herein,we report a heterogeneous structure coupling NiFe-MOF nanoparticles with NiS nanosheets onto Ni foam(denoted as the NiFe-MOF@NiS/NF)via the mild strategy involving sulfur-modified corrosion and electrodeposition treatment.The constructed amorphous/crystalline interfaces could not only facilitate the adequate infiltration of electrolyte and release of O_(2) bubbles at large current densities,but also significantly improve the charge transfer from NiFe-MOF to NiS and the adsorption/desorption capacity of oxygen intermediates.Intriguingly,during oxygen evolution reaction process,the sulfate film formed by the self-reconstruction could remarkably inhibit the adsorption of Cl–ions on the catalyst surface in the seawater electrolytes.Benefiting from the robust corrosion resistance,unique amorphous/crystalline interfaces,and the charge redistribution,the well-designed NiFe-MOF@NiS/NF exhibits the low overpotential of 346 and 355 mV under a high current density of 500 mA cm^(‒2)in alkaline water and seawater electrolytes,respectively.More importantly,the as-fabricated NiFe-MOF@NiS/NF demonstrates prolonged stability and durability,lasting over 600 h at a current density of 100 mA cm^(‒2)in both electrolytes.This study enriches the understanding of electronic structure modulation and chlorine corrosion resistance in seawater,providing broad prospects for designing advanced MOF-based catalysts.

关 键 词：金属有机框架 非晶/晶异质界面 电催化 海水氧化 大电流密度 

分 类 号：TQ116.2[化学工程—无机化工] TQ426