Enhanced Electrocatalytic Hydrogen Oxidation on Ni/NiO/C Derived from a Nickel‐Based Metal–Organic Framework

Abstract

The sluggish hydrogen oxidation reaction (HOR) under alkaline conditions has hindered the commercialization of hydroxide-exchange membrane hydrogen fuel cells.Alowcost Ni/NiO/C catalyst with abundant Ni/NiO interfacial sites was developed as acompetent HOR electrocatalyst in alkaline media. Ni/NiO/C exhibits an HOR activity one order of magnitude higher than that of its parent Ni/C counterpart. Moreover,N i/NiO/C also shows better stability and CO tolerance than commercial Pt/C in alkaline media, which renders it av ery promising HOR electrocatalyst for hydrogen fuel cell applications.D ensity functional theory (DFT) calculations were also performed to shed light on the enhanced HOR performance of Ni/NiO/C;the DFT results indicate that both hydrogen and hydroxideachieveoptimal binding energies at the Ni/NiO interface,resulting from the balanced electronic and oxophilic effects at the Ni/NiO interface.Along with the rapid progress in the generation of clean hydrogen from water with renewable energy sources such as solar and wind energies,i ncreasing attention has been devoted to the efficient utilization of hydrogen directly as agreen fuel, in that the sole product of hydrogen combustion is water. Within this context, the hydrogen fuel cell is one of the most promising technologies for hydrogen utilization. [1] Even though commercial hydrogen fuel cells employing proton exchange membranes exhibit high power output, [2]

Insight into the hydrogen oxidation electrocatalytic performance enhancement on Ni via oxophilic regulation of MoO2

“…As shown in Ni 2p region (Fig. 1f), the peak at about 852.4 eV is assigned to Ni 0[26], the low content of Ni 0 in Ni/MoO 2 is attributed to the unavoidable oxidation at surface the of small particle size. For both Ni-MoO 2 and Ni/MoO 2 , the peaks centred in 232.4 and 229.3 eV of Mo 3d region(Fig.…”

“…Inspired by this, a series of electrocatalysts with bi-active sites consisting of metals and metal oxides/hydroxide have been reported, in which the metal acts as the hydrogen adsorption site and the other component promotes OH ad adsorption [22][23][24][25]. Ni/NiO/C with enhanced HOR performance in alkaline medium was synthesized by Sun's group [26]. Luo and co-workers [27] improved the HOR activity of Ni by combining with oxygen-vacancy-rich CeO 2 .…”

Defect Engineering for Fuel‐Cell Electrocatalysts

“…Unfortunately, Ni adsorbs hydrogen relatively strongly, limiting the breakage of HH bonds and suppressing the HOR process. [92] Therefore, weakening the hydrogen binding energy of Ni species is the most direct and useful strategy to accelerate HOR kinetics over such catalysts. Accordingly, Luo's group have constructed oxygen-vacancy-rich CeO 2 /Ni heterostructures in which the electrons from Ni are transferred to oxygen-vacancy-rich CeO 2 for enhancing HOR activity.…”

Inter-regulated d-band centers of the Ni3B/Ni heterostructure for boosting hydrogen electrooxidation in alkaline media

“…3d, Tables S2 and S3 †). [16][17][18][19][20]22,24,[38][39][40][41] The exchange current densities (j 0 ) on these Ni-based catalysts could be further extracted by tting the kinetic current densities according to the Butler-Volmer equation (Fig. 3c).…”

“…S11 †) ), respectively, and is even comparable to those of some Pd-based catalysts (Tables S2 and S3 †). 10,[16][17][18][19][20]24,[38][39][40][41][42][43] In order to avoid the contribution from non-faradaic current, a steady-state polarization curve was also obtained for comparison to separate the hydrogen electrocatalytic response as shown in Fig. S12.…”