Co2FeO4@rGO composite: Towards trifunctional water splitting in alkaline media

First‐Row Transition Metals for Catalyzing Oxygen Redox

“…Zhan et al [315] prepared an excellent NiFe bifunctional electrocatalyst for OER and ORR with a plate-like morphology (Figure 14a,b) via a onepot solvothermal method followed by a chemically reductive approach with the aid of hydrazine hydrate and ammonia water, as shown in Figure 14c. Hanan et al [316] found that hydrazine is not only the reducing agent during the transition from induced graphene oxides to reduced graphene oxides but also the stabilizing agent in the process of nanostructured material synthesis. In the synthesis process, hydrazine was added dropwise into the well-dissolved precursor solution under constant stirring at room temperature, and then treated at high temperatures to obtain Co 2 FeO 4 @rGO systems as trifunctional electrocatalyst towards HER, OER, and ORR via simultaneous hydrothermal and reduction method (Figure 14d), which exhibited sphere like architecture (Figure 14e,f) and well-dispersed nanoparticles with different shapes (Figure 14g,h) Photochemical reduction method has been applied in the electrocatalyst preparation due to its facile synthesis process, lowcost chemical reagents, and hypotoxicity.…”

“…d) Illustration of tri-functional electrocatalyst of Co2FeO4@rGO composite, SEM images of e) Co 2 FeO 4 and f) CFG-10 composite, HRTEM images of g) Co 2 FeO 4 and h) CFG-10 composite. Reproduced with permission [316]. Copyright 2022, Elsevier.…”

Ni–Pd Nanocomposites on Reduced Graphene Oxide Support as Electrocatalysts for Hydrogen Evolution Reactions

“…Graphene oxide (GO) a two-dimensional derivative of graphene has numerous oxygen functional groups, incorporated into its structure. Previously, we demonstrated that these groups are responsible for binding transition metal ions via the coordination mechanism. − Thus, GO is a great candidate for structural support, since this bonding not only provides dense uniform coverage of the surface with metals but also enhances catalytic activity and stability of metals during electrochemical processes. , …”

“…40−43 Thus, GO is a great candidate for structural support, since this bonding not only provides dense uniform coverage of the surface with metals but also enhances catalytic activity and stability of metals during electrochemical processes. 44,45 The aim of this research is to investigate if the joint deposition of Ni 2+ and Pd 2+ ions on GO and subsequent chemical reduction lead to the formation of the mixed Ni−Pd particles or particles of individual metals will be formed. We explore the structural features of the synthesized composites and perform the initial screening of their applicability for hydrogen evolution reaction (HER) in comparison with monometallic analogues containing separately nickel or palladium.…”

CoO–Co Heterojunction Covered with Carbon Enables Highly Efficient Integration of Hydrogen Evolution and 5-Hydroxymethylfurfural Oxidation

“…In view of the scarcity and the high price of precious metals, transition metal-based electrocatalysts with a fascinating d -band electronic structure have attracted wide attention recently [ 32 , 33 , 34 , 35 ]. In particular, the multi-valence feature of transition metals provides the possibility to construct multiple different catalytic sites in the same catalyst [ 21 , 32 , 36 , 37 ]. Previous studies have corroborated that, due to the carbothermal reduction reaction, some transition-metal species can be reduced by the carbon generated from the peripheral organic ligands at a high temperature, thus producing the heterojunction of metal and metal oxide [ 38 , 39 , 40 ].…”