High‐Performance Bismuth‐Doped Nickel Aerogel Electrocatalyst for the Methanol Oxidation Reaction

Abstract

Low-cost, non-noble-metal electrocatalysts are required for direct methanol fuel cells,b ut their development has been hindered by limited activity,high onset potential, low conductivity,a nd poor durability.Asurface electronic structure tuning strategy is presented, which involves doping of aforeign oxophilic post-transition metal onto transition metal aerogels to achieve an on-noble-metal aerogel Ni 97 Bi 3 with unprecedented electrocatalytic activity and durability in methanol oxidation. Trace amounts of Bi are atomically dispersed on the surface of the Ni 97 Bi 3 aerogel, which leads to an optimum shift of the d-band center of Ni, large compressive strain of Bi, and greatly increased conductivity of the aerogel. The electrocatalyst is endowed with abundant active sites, efficient electron and mass transfer,r esistance to CO poisoning, and outstanding performance in methanol oxidation. This work sheds light on the design of high-performance non-noblemetal electrocatalysts.

Nickel Iron Diselenide for Highly Efficient and Selective Electrocatalytic Conversion of Methanol to Formate

“…Ni 0.75 Fe 0.25 Se 2 electrodes displayed the largest ECSA values among the series tested, 62.5 cm 2 g −1 , well above the value obtained for NiSe 2 electrodes, 18.75 cm 2 g −1 (Figure S10, Supporting Information). These values were below those reported for branched Ni 3 C particles, 108.6 cm 2 g −1 , [ 26 ] and Ni 97 Bi 3 aerogels, 176.6 cm 2 g −1 , [ 58 ] but well above those of branched Ni 0.75 Cu 0.25 , 0.12 cm 2 g −1 , [ 59 ] and NiO nanotubes, 36.25 m 2 g‐ 1 . [ 60 ]…”

Selective Methanol‐to‐Formate Electrocatalytic Conversion on Branched Nickel Carbide

“…Among the several alternative materials proposed to replace noble metals as MOR catalysts, Ni offers the highest cost‐effectiveness. A plethora of Ni [12–14] and Ni‐based catalysts, including oxides/hydroxides, [15–17] metal alloys, [18–23] phosphides, [24] chalcogenides, [25] and nitrides, [26] have been developed and tested toward MOR. Surprisingly, the nickel carbide, which a priori offers suitable properties as electrocatalysts, for example, stability, electrical conductivity and element abundance, has not been tested toward MOR.…”

Boosting Both Electrocatalytic Activity and Durability of Metal Aerogels via Intrinsic Hierarchical Porosity and Continuous Conductive Network Backbone Preservation

“…Unsupported electrocatalysts, such as nanotubes, [ 8 ] metal aerogels, [ 17–27 ] mesostructured thin films, [ 28,29 ] nanodendrites, [ 30 ] etc. provide opportunities to solve the problem of carbon corrosion.…”

“…[ 17–27 ] The porous architectures in metal aerogels could offer numerous open and free channels for rapid mass diffusion, and the interconnected, ultrathin, and tailorable metallic nanowire network backbones could facilitate the electron transfer rate and provide an abundant reactive site contributed by defects, kinks, alloyed effect, etc. [ 17–27 ] Driven by these characteristics favorable for electrocatalysis, metal aerogels have attracted great attention and found promising applications in wide electrochemical areas, such as ORR, [ 17 ] ethanol oxidation reaction, [ 18 ] bio‐fuel cells, [ 19 ] colorimetric sensing, [ 20 ] water splitting, [ 21 ] carbon dioxide reduction, [ 22 ] photoelectrocatalysis, [ 23 ] etc. Despite these encouraging and remarkable works, there are still great challenges for promoting metal aerogels into practical applications, among which how to overcome the collapse of the intrinsic hierarchical porous and continuous conductive network structure of metal aerogels during electrode preparation is vital but did not attract sufficient attention.…”