Electrodeposited Transition Metal Electrocatalysts For Full Water Splitting

There are two half reactions in water splitting,oxygen evolution reaction(OER)and hydrogen evolution reaction(HER),respectively.It is necessary to use electrocatalysts to solve electrode polarization during water splitting.Transition metal has been an attractive option for bifunctional electrocatalysts due to rich reserves and low costs.Electrodeposition is a feasible method to synthesize electrocatalysts due to its facility and mild reaction conditions.In this study,a series of porous nanostructured Ni-Fe bimetallic selenides(NixFei-xSe2/NF)were synthesized via Amperometic i-t Curve(A i-t),a method of electrodeposition.All these bifunctional electrocatalysts own good performance for both OER and HER when measured in 0.1 M KOH.And NixFei-xSe2/NF-1:2(in which Ni/Fe input molar ratio is 1:2)has the best OER/HER performance at the same time.For a defined current density of 50 mA/cm2,the NixFe1-x,Se2/NF-1:2 requires a very low overpotential and small Tafel slope for OER,viz 283 mV and 39.9 mV·dec-1.For a defined current density of-10mA/cm2,the NiXFe1-X?Se2/NF-1:2 requires a low overpotential for HER,viz 192 mV while Tafel slope is 149.5 mV-dec-1.A NixFe-xSe2/NF-1:2-based two-electrode alkaline water splitting system affording 10 mA/cm2 at a cell voltage of 1.71 V in 50000 s run.A series of Co-Mn bimetallic oxides(CoxMn1-XO/NF/G)were synthesized via electrodeposition including Multi-Current Steps(MS),Cyclic Voltammetry(CV)and Chronopotentionmetry(CP).The MS-CoxMn1-xO/NF/G-1:2(in which Co/Mn input molar ratio is 1:2)has the best performance of OER when measured in 0.1 M KOH.For a defined current density of 10 mA/cm2,the MS-CoxMn1-XO/NF/G-1:2 requires a very low overpotential for OER,viz 304 mV and 91.3 mV-dec-1.As for CV-CoXMni-XO/NF/G-1:2 and CP-CoXMn1-xO/NF/G-1:2,their overpotentials are 327 mV and 338 mV,respectively.