Co掺杂Cu₂S的制备及其电催化析氢性能研究

Preparation and Electrocatalytic Hydrogen Evolution Performance of Co-Doped Cu₂S

摘要: 针对非贵金属电催化剂应用于析氢反应(HER)过程中普遍存在的活性位点数量有限，电荷传输动力学缓慢的问题，本文采用室温氧化–水热两步法在泡沫铜基底上原位制备了不同Co掺杂量的Cu₂S催化剂，系统研究了Co掺杂对Cu₂S晶体结构、微观形貌、电子态及HER催化性能的影响。XRD和XPS结果表明，Co²⁺成功嵌入Cu₂S晶格，引起晶格膨胀且未形成独立杂质相；SEM显示Co掺杂诱导形成了均匀致密的纳米团簇结构，显著增大了电化学活性表面积。电化学测试表明，在1 M KOH中，Co₃₀Cu₂S达到50 mA∙cm⁻²电流密度仅需200 mV过电位，Tafel斜率为147 mV∙dec⁻¹，电荷转移电阻显著降低，且连续12 h稳定性测试未见明显衰减。Co掺杂通过晶格畸变、电子结构重排及电荷传输效率提升的三重协同作用，优化了H*吸附能并加速了碱性HER的Volmer步骤。本研究为设计高效、稳定的非贵金属硫化物HER催化剂提供了一定的实验参考与机理分析思路。

Abstract: Aiming at the prevalent issues of insufficient active sites and sluggish charge transfer kinetics in the hydrogen evolution reaction (HER) of non-noble metal electrocatalysts, herein, a room-temperature oxidation-hydrothermal two-step strategy was adopted to in-situ synthesize Cu₂S catalysts with different Co doping contents on copper foam substrates. The effects of Co doping on the crystal structure, micromorphology, electronic state and HER catalytic performance of Cu₂S were systematically investigated. XRD and XPS results confirm that Co²⁺ is successfully incorporated into the Cu₂S lattice, inducing lattice expansion without the generation of independent impurity phases. SEM characterization reveals that Co doping triggers the formation of uniform and dense nanocluster structures, which greatly enlarges the electrochemically active surface area. Electrochemical measurements demonstrate that the Co₃₀Cu₂S catalyst only requires an overpotential of 200 mV to achieve a current density of 50 mA∙cm⁻² in 1 M KOH solution, with a Tafel slope of 147 mV∙dec⁻¹ and distinctly reduced charge transfer resistance. Moreover, no obvious performance degradation is observed after a 12-hour continuous stability test. Through the triple synergistic effects of lattice distortion, electronic structure rearrangement and accelerated charge transport efficiency, Co doping optimizes the adsorption energy of H* intermediates and facilitates the Volmer step of alkaline HER. This work provides experimental references and mechanistic insights for the rational design of high-efficiency and stable non-noble metal sulfide electrocatalysts toward HER.