Construction of free-standing electrode anchored on polyimide foam with a facile synergistic strategy for enhancing hydrogen peroxide reduction electrocatalysis

A rational design and selection of electrocatalytic cathode host materials are significant to achieve sustainable, efficient and stable catalysis towards H 2 O 2 electroreduction. Herein, we described a facile synergetic strategy to generate a novel free-standing electrode (Pd-Co 3 O 4 /3D RGO@polyimide (PI) foam, PCRP) with well-developed porous and hollow structure, which derived from cobalt-based MOFs (ZIF-67) as an advanced Pd host, rooting on the 3D conductive graphene/PI foam to realize the significant promotion towards H 2 O 2 electroreduction. Such 3D hollow structure design not only offers a high specific area to develop a number of exposed catalytic activity sites but also restricts the aggregation of nanoparticle catalysts within catalysis. Utilizing the electrode structural advantages and reducing the particle diameter of noble metal catalysts to improve the catalytic performance was possible. When evaluated as a co-catalyst for H 2 O 2 electroreduction, the as-developed electrode displayed an optimized reduction current density of 962 mA·cm −2 at −0.8 V in alkaline due to the synergetic influence of Pd nanoparticles and Co 3 O 4 hollow cages. Notably, the loading of noble metal on the PCRP electrode was only close to 2.0 wt% in Pd-Co 3 O 4 hybrids. What's more, the obtained PCRP electrode also exhibited robust stability, low apparent activation energy (9.071 kJ·mol −1 ), good reproducibility and repeatability (903 mA·cm −2 after 1000 cycles with a 0.0058% current density decay per cycle at −0.8 V) superior to that of single Co 3 O 4 nanoparticles or Co 3 O 4 /3D RGO hybrids with simple configuration, implying its great promise for novel energy transformation systems. • A Pd-Co 3 O 4 /3D RGO@polyimide (PCRP) electrode was successfully developed. • Hollow structure Co 3 O 4 derived from MOFs as Pd host supported on graphene substrate. • The electrode presented characteristics of small particle diameter and low loading of Pd. • The synergism of structure and constituent promoted electrocatalytic performance. • The electrode exhibited excellent stability, reproducibility, low apparent activation energy.