Study Of Electrocatalytic Performance Of NiCu Alloys And Poly-AMT For Hydrogen Evolution

Hydrogen is an ideal fuel and energy carrier due to the advantages of no pollution, high energy density, and easy conversion into available energy forms. Highly purified hydrogen can be produced from water electrolysis, but the large-scale electrolysis is reatrained by high energy consumption. Development of synthesizing highly catalytic cathode materials for lowering the overpotential of hydrogen evolution reaction (HER) grew a new impulse to researches. In this article, a study about the electrocatalytic effect of NiCu nanoalloy and 2-Amino-5-mercapto-1,3,4-thiadiazole (AMT) modified on different substrates for HER.Different atom ratio of NiCu nanoalloys were galvanostatically deposited on a Cu substrate for catalyzing HER in H2SO4 electrolytes. The morphology and composition of the deposits were characterized by FE-SEM/EDX analysis. The change of deposition current density resulted in various composition of nanoalloy. The dendrictic NiCu nanopearl chains in 1:1 atom ratio is prepared at the deposition current density of 50 mA cm-2. Dendritic NiCu nanopearl chains in 1:1 atom ratio were galvanostatically deposited on a Cu substrate for catalyzing HER in H2SO4 electrolytes. The morphology and composition of the deposits were characterized by FE-SEM/EDX analysis. All the four-level branches of the dendritic nanoalloy grew in a nanopearl chain structure with a diameter of ca.50-80 nm. The electrocatalytic activity to HER was studied by linear polarization, electrochemical impedance spectroscopy (EIS) and chronopotentiometry. The exchange current density of HER at the NiCu nanoalloy was found to be 2836 and 8.5 times higher than at Cu and Ni/Cu, while the overpotential at a current density of 50 mA cm-2 was decreased by ca.265 and 135 mV relative to Cu and Ni/Cu, respectively. Both the EIS and chronopotentiometry indicate that the NiCu nanoalloy can not only significantly reduce the charge transfer resistance of HER, but also facilitate the elimination of the generated hydrogen from the active sites. This work indicates that the dendritic NiCu nanochains may be a potent candidates as a non-noble metal catalyst for hydrogen energy production.A conductive polymer, poly (2-amino-5-mercapto-1,3,4-thiadiazole) (PAMT), was electrodeposited on a glassy carbon substrate for electrocatalyzing HER in H2SO4 electrolytes. The prepared material was characterized by scanning electron microscope and X-ray photoelectron spectroscopy. The surface of the PAMT film was uniform, crack-free, and was full of curly short filaments (<100 nm long). The free active sites of the PAMT for HER could be represented as -N=,which exist in pairs meeting the dual-site requirements for H-H combination. The Tafel analysis revealed that the open circuit potential was positively shifted by 313 mV due to the PAMT catalyst, with a prominent decrease in activation energy. Both the electrochemical impedance spectroscopy and chronopotentiometry suggested that the PAMT can not only significantly reduce the charge transfer resistance of the HER, but also facilitate the desorption of the generated hydrogen from the active sites. These results indicate that the N- and S-rich conductive polymers deserve further investigation as potential electrocatalyst candidates for hydrogen energy production.Different substrates for electrocatalysis have different effects. A conductive polymer AMT is coated on sCPE and GCE substrate to investigate the effect of different carbon-based supports for HER in acid electrolytes. The distinction with PAMT film deposits by different cycle scans is cleared. PAMT can enhance the exchange current density of HER by 647 times on PAMT/sCPE with the 100 cycle scans of electropolymerization PAMT and PAMT/GCE electrode enhance the exchange current density by 533 times with 60 cycle scans compared to the sCPE and GCE, respectively. Also, PAMT/sCPE can reduce the HER activation energy by 65%, whereas the PAMT/GCE electrode have the lower decrease by 48%. As a result, sCPE may be the better carbon electrode towards GCE as a supports of PAMT polymer film for HER.