Ni_(2)P/Cu(OH)_(2)催化剂的制备及其全解水性能研究

Preparation of Ni_(2)P/Cu(OH)_(2)as efficient electrocatalyst for water splitting

通过化学处理法在泡沫铜基底表面生成Cu(OH)_(2)纳米线,大大增加了基底材料的表面积和导电性.采用水热法在Cu(OH)_(2)纳米线表面制备片状Ni-CH/Cu(OH)_(2)前驱体,对Ni-CH/Cu(OH)_(2)前驱体进行低温磷化得到多级结构Ni2P/Cu(OH)_(2)催化剂.通过扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)和X射线衍射仪(XRD)对催化剂的物质结构和表面形貌进行了表征.采用线性伏安法、恒电位等技术对催化剂的电化学性能进行测试.在1.0 mol·L^(-1)KOH碱性溶液中,当电流密度为10 mA·cm^(-2)时,Ni_(2)P/Cu(OH)_(2)的析氢反应(HER)和析氧反应(OER)过电位分别为133和333 mV,且均具有较好的稳定性.将这种多级结构Ni_(2)P/Cu(OH)_(2)催化剂分别用作阳极和阴极进行全解水电解,电流密度达到10 mA·cm^(-2)时所需电势仅为1.69 V,表现出优异的全解水催化性能.良好的电催化性能主要归因于泡沫铜较好的导电性以及这种多级结构催化剂能增大催化剂的表面积,可提供更多的电子传输孔道,暴露更多的活性位点.

In this work,self-supported hierarchical structure Ni_(2)P/Cu(OH)_(2)catalysts on copper foam are developed.The synthetic process involves three steps of chemical reactions.In the first step,Cu(OH)_(2)nanowires are generated on the surface of copper foam by chemical treatment.In the next step,the Ni-CH/Cu(OH)_(2)precursors are synthesized on the surface of Cu(OH)_(2)nanowires by hydrothermal method.In the final step,the hierarchical structure Ni_(2)P/Cu(OH)_(2)catalysts are prepared from the Ni-CH/Cu(OH)_(2)precursors by a low-temperature phosphidation reaction.The material structure and surface morphology of the catalysts are characterized by scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS)and X-ray diffractometry(XRD).The obtained hierarchical structure Ni_(2)P/Cu(OH)_(2)catalysts show excellent hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)performances in 1.0 mol·L^(-1)KOH alkaline solution with low overpotentials of 133 and 333 mV at a current density of 10 mA·cm^(-2),respectively.The hierarchical structure Ni_(2)P/Cu(OH)_(2)catalysts are used both as anode and cathode for complete water electrolysis.It requires an applied cell voltage of only 1.69 V to deliver a current density of 10 mA·cm^(-2)in water electrolysis showing excellent catalytic performance of total hydrolysis.In addition,the Ni_(2)P/Cu(OH)_(2)catalysts can keep a steady current density of 10 mA·cm^(-2)for 20 h at an cell voltage of only 1.69 V.The outstanding electrochemical performance of the electrode for water splitting application is attributed to the high conductivity of the copper foam and the specific structure of the electrode with large interfacial area can provide more electron transport channels,expose more active sites.