A new concept analogous to homogeneous catalysis to construct in-situ regenerative electrodes for long-term oxygen evolution reaction

Ultra-small Ru nanoparticles embedded on Fe–Ni(OH)2 nanosheets for efficient water splitting at a large current density with long-term stability of 680 hours

“…18,19 However, the complexity of the composition and structure increases the difficulty of active site identification, so employing a facile method to prepare bifunctional catalysts equipped with well-defined active sites is crucial. NiFe metal oxide/hydroxide/oxyhydroxide have been extensively considered as the optimal metal combination to effectively catalyze the OER and our previous research demonstrated that NiFe hydroxide can be prepared easily via a simple physical adsorption of metal ion method at room temperature, 20–22 but on the other hand, their HER activity is unimpressive. Recent results indicated that Ru (Ru–Ni SNs, 23 Ru–MoO 2 , 24 Ni 3 Co x @Ru HNS, 25 RuNi–NSs@PANI, 26 RuPt/OMC, 27 and Ru 1 @Co/NC 28 ) displays comparable HER activity with Pt/C, thanks to the optimal H adsorption free energy.…”

Three-dimensional hierarchical Co(OH)F nanosheet arrays decorated by single-atom Ru for boosting oxygen evolution reaction

“…As depicted in Fig. 2f, the EXAFS spectra of Co K-edge show the shortened bond length (1.634 Å) of the nearest shell of SA-Ru/ Co(OH)F compared with that of bare Co(OH)F (1.641 Å), which is closely related to the increased oxidation of Co ions [43,45,46]. Because the Co 2+ is oxidized to close to Co 3+ during the oxygen evolution, the bond length for the first coordination shell of SA-Ru/Co(OH)F-A is further contracted to 1.628 Å.…”

“…2e. The Co K-edge XANES of SA-Ru/Co(OH)F exhibits a more positive energy compared with Co(OH)F, but lower than CoOOH [43], indicating the oxidation state of Co in SA-Ru/ Co(OH)F is between +2 and +3. After OER testing, the absorption peak of SA-Ru/Co(OH)F-A further evidently right-shifts to 7726.6 eV, much close to that of CoOOH, demonstrating the oxidation of initial Co 2+ to a higher state during the OER process [44].…”

Tuning Reconstruction Level of Precatalysts to Design Advanced Oxygen Evolution Electrocatalysts

“…The dissolution of metals (e.g., alkaline and alkaline earth elements) into electrolytes to induce surface reconstruction is widely reported in relation to the design of high-performance electrocatalysts [ 14 , 89 , 110 , 126 , 127 , 128 ]. The observed electrocatalytic process is highly dependent on the dissolution rate and the final surface species, which form; this is also related to the applied potential and time under an anodic condition [ 84 , 128 , 129 ]. Thus, the continuous dissolution may be a drawback in terms of long-term application.…”

“…For practical applications, a high current density, high potential, and high gas production rate are often involved; the shedding and dissolution of the catalysts are tough problems to solve [ 23 , 130 , 132 , 133 ]. To avoid these intractable issues, very recently the Cao group proposed a novel concept similar to homogeneous catalysis to fabricate in situ regenerative electrodes that could exhibit high OER activity and superior long-time stability level when operated at a high current density [ 129 ]. Specifically, precatalysts were demonstrated as the Co and Fe bimetal salt solutions, which were mixed with an alkaline solution before the reaction.…”