氧化石墨烯生长钨基氧化物酸环境电催化析氢

Hydrogen evolution reaction for tungsten-based oxides grown on graphene oxide in acidic environment

以磷钨酸为钨源,单层氧化石墨烯(GO)为载体,引入碳纳米管(CNTs),通过一步水热法和在空气中煅烧制备了纳米异质结(WO_(3)-r GO-CNTs)。通过FTIR、XRD、XPS、TG、SEM、EDS、TEM和BET对其进行了表征,利用线性伏安法和循环伏安法对其进行了电催化析氢(HER)反应测试。结果表明,WO_(3)晶体粒子均匀、有序地分布在单层GO和CNTs的表面上。WO_(3)-r GO-CNTs在酸性电解质中表现出优异的HER催化活性。当电流密度为10 m A/cm^(2)时,其过电势为218 m V,Tafel斜率为130.5 mV/dec。当过电势为–0.5 V vs.可逆氢电极(RHE)时,其阻抗为8.2Ω。同时,WO_(3)-r GO-CNTs可以在218m V(电流密度为10m A/cm^(2))过电势下,保持50 h的稳定性和耐久性,其双层电容为1.20 mF/cm^(2)。WO_(3)晶体与GO和CNTs间异质结结构的存在产生了协同效应:GO为WO_(3)晶体提供了广阔的金属反应活性位点,而CNTs则提供了利于电子传输的活性轨道。

Nano heterojunction(WO_(3)-rGO-CNTs)was synthesized using phosphotungstic acid and single-layer graphene oxide(GO)as tungsten source and carrier and introducing carbon nanotubes(CNTs)by one-step hydrothermal method and calcination in air.The sample was characterized by FTIR,XRD,XPS,TG,SEM,EDS,TEM and BET.The performance of WO_(3)-rGO-CNTs for hydrogen evolution reaction(HER)was tested by linear sweep voltammetry and cyclic voltammetry.The results showed that WO_(3) crystals were uniformly and orderly distributed on the surface of single-layer GO and CNTs.After introduction of CNTs,prepared WO_(3)-r GO-CNTs exhibited excellent HER catalytic activities in an acidic electrolyte.At 10 m A/cm^(2),the overpotential was 218 m V and the Tafel slope was 130.5 m V/dec.At an overpotential of–0.5 V vs.reversible hydrogen electrode(RHE),the impedance was 8.2Ω.Meanwhile,WO_(3)-r GO-CNTs could maintain long-term stability and durability for up to 50 h at an overpotential of 218 m V(current density of 10 mA/cm^(2)),while its double-layer capacitance was 1.20 mF/cm^(2).WO_(3) crystals,GO and CNTs had synergistic effect due to the existence of heterogeneous structure.GO provided wide metal reaction active sites for WO_(3) crystals,while CNTs provided active orbitals conducive to electron transport.