CoP修饰Ti_(3)C_(2)T_(x)MXene纳米复合材料作为高效析氢反应电催化剂

CoP Decorated on Ti_(3)C_(2)T_(x)MXene Nanocomposites as Robust Electrocatalyst for Hydrogen Evolution Reaction

高效、经济和环保是电化学水分解制氢电催化剂的关键要素。二维(2D)MXene材料因其独特的物理化学性质而受到广泛关注。虽然有许多不同种类的MXene材料,但只有少数具有本征析氢反应(HER)催化活性。然而,MXene材料具有很多优点,如较大的比表面积、高电导率和丰富的表面官能团,因此可以作为与其他物质复合的理想平台。本研究首先通过密度泛函理论(DFT)预测了CoP与Ti_(3)C_(2)T_(x)MXene(其中T_(x)=―F和―OH官能团)具有低的氢吸附自由能(ΔGH^(*))。接着,我们合成了CoP-Ti_(3)C_(2)T_(x)MXene纳米复合材料,并在0.5 mol∙L^(−1)H_(2)SO_(4)中测试了其电催化HER性能。该材料在电流密度为10 mA∙cm^(−2)时表现出了低的过电位(135 mV)和Tafel斜率为48 mV∙dec^(−1)。理论计算表明,CoP-Ti_(3)C_(2)T_(x)MXene纳米复合材料的优异电催化性能源于Ti_(3)C_(2)T_(x)的高金属导电性、良好的界面电荷转移、快速的氢吸附/解吸过程以及优化的电子结构。

Electrocatalysts play a pivotal role in the electrochemical water splitting process to produce hydrogen fuel.The advancement of this technology relies on the development of efficient,cost-effective,and readily available electrocatalysts.Two-dimensional(2D)MXene materials have garnered significant attention due to their unique physicochemical properties,rendering them promising candidates for electrocatalytic applications.While there are numerous types of MXene materials available,only a few possess intrinsic hydrogen evolution reaction(HER)catalytic activity.However,MXene materials can serve as excellent platforms for enhancing catalytic HER activity by combining them with other substances,owing to their large specific surface area,high conductivity,and abundant surface functional groups.In this study,we initially conducted a predictive analysis using density functional theory(DFT)to assess the potential of combining CoP with Ti_(3)C_(2)T_(x)MXene materials(where T_(x)represents―F and―OH functional groups)in reducing the adsorption free energy of hydrogen(ΔGH^(*)).The results indicated that the CoP-Ti_(3)C_(2)T_(x)nanocomposites exhibited aΔGH^(*)value approaching 0,suggesting promising HER performance.Following this theoretical prediction,we synthesized the CoP-Ti_(3)C_(2)T_(x)MXene nanocomposites.Comprehensive characterization of the synthesized nanocomposites was performed using various techniques,including scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).These analyses confirmed the successful decoration of CoP on the MXene nanosheets and provided insights into the structural and compositional properties of the nanocomposites.Furthermore,we evaluated the electrochemical performance of the CoP-Ti_(3)C_(2)T_(x)nanocomposites through linear sweep voltammetry and chronoamperometry measurements.The results demonstrated superior catalytic activity and stability for the HER compared to pure Ti_(3)C_(2)T_(x)and CoP catalysts.Specifically,the as-synthesized CoP-Ti_(3)C_(2)T_(x)MXene nanocomposites exhibited remarkable electrocatalytic HER kinetics,featuring a low overpotential of 135 mV at a current density of 10 mA∙cm^(−2) and a small Tafel slope of 48 mV∙dec^(−1)in a 0.5 mol∙L^(−1)H_(2)SO_(4)solution,with the electrocatalyst maintaining stability for up to 50 h.Subsequent theoretical calculations were conducted to elucidate the factors contributing to the exceptional electrocatalytic performance of the CoP-Ti_(3)C_(2)T_(x)MXene nanocomposites.It was determined that the metallic conductivity of Ti_(3)C_(2)T_(x)MXene materials,well-structured interface charge transfer,and optimized electronic structure of CoP played significant roles in enhancing catalytic activity.In conclusion,this study underscores the potential of CoP-decorated Ti_(3)C_(2)T_(x)MXene nanocomposites as promising electrocatalysts for efficient HER in various energy conversion and storage devices.These findings represent a significant contribution to the development of robust and efficient catalysts for hydrogen generation,a critical component of renewable energy applications and sustainable development.