Ultrathin Pd Te Nanowires Anchoring Reduced Graphene Oxide Cathodes For Efficient Hydrogen Evolution Reaction

With the decreasing availability of fossil fuels and increasing demand for clean energy, hydrogen, which has high specific energy storage density and perfect environmental friendliness, is increasingly considered as the fuel of the future. Nowadays, water splitting has been considered as the best method to produce hydrogen. As an important half reaction used to couple with OER in water splitting, HER has been studied extensively. Compared with acidic media, HER in alkaline media generally requires higher overpotentials and associated with large consumption. Thus, the development of catalysts should aim to reduce the overpotential and consequently increase the efficiency. Therefore, design and synthesis of efficient electrocatalysts for hydrogen evolution reaction under all pH conditions is extremely desirable but still remains a challenge. Here a facile method to decorate PdTe nanowires on the reduced graphene oxide nanosheets(PdTe NWs/rGO) has been developed. We would like to brief the importance and novelty of this work as follows:(1) A simple strategy to integrate PdTe NWs and rGO as an excellent electrocatalyst for hydrogen evolution reaction(HER).In this study, we developed a green, facile and easily scalable strategy to anchor 1D ultrathin PdTe NWs to 2D rGO nanosheets without any additional surfactant or adhesive. The synergetic effect between PdTe NWs and rGO sheets are extensively employed. rGO sheets are demonstrated to serve as not only support but also the reductant and stabilizer, which can improve the HER activity and stability, dramatically. Moreover, the composition of the hybrid is controllable by changing the adding amount of precursors.(2) Excellent activity and long-term stability in both acidic and alkaline media.In this communication, we demonstrate an optimized Pd/Te and PdTe/rGO ratio without superfluous waste. Electrochemical tests show that the onset potential of Pd3.02 Te NWs/rGO was as low as-7 mV vs. RHE and it maintains its catalytic activity for at least 48 h in alkaline media. It only requires overpotentials(η) of 97 mV, 154 mV and 355 mV to afford current density of 10, 20 and 100 mA cm-2, respectively. Besides, the Pd3.02 Te NWs/rGO also exhibits excellent performance in acidic media. It shows an onset potential of-6 mV vs. RHE. To attain a current density of 10 mA cm-2, the Pd3.02 Te NWs/rGO needs an overpotential of 48 mV. Interestingly, the Tafel slope and the exchange current density values associated with hydrogen evolution reaction are determined to be 90 mV dec-1 and 1.848 mA cm-2 in alkaline and 63 mV dec-1 and 1.807 mA cm-2 in acid, respectively.This work not only reports a simple fabricated catalyst as feasible Pt-base material replacement for efficient water electrolysis, but also offers a new horizon toward controllable fabrication of warying types of NWs/rGO hybrids in the energy material fields. To the best of our knowledge, this is the first time that Te-based NWs/rGO hybrid was used as a HER catalyst.