Engineering Active Iron Sites on Nanoporous Bimetal Phosphide/Nitride Heterostructure Array Enabling Robust Overall Water Splitting

Abstract

Alkaline water electrolysis is a commercially viable technology for green H 2 production using renewable electricity from intermittent solar or wind energy, but very few non-noble bifunctional catalysts simultaneously exhibit superb catalytic efficiency and stability at large current densities for hydrogen and oxygen evolution reactions (HER and OER, respectively), especially for ironbased catalysts. Given that iron is the most abundant and least expensive transition metal, iron-based compounds are very attractive low-cost targets as active electrocatalysts for bifunctional water splitting with large-current durability. Herein, the in situ construction of a self-supported Fe 2 P/Co 2 N porous heterostructure arrays possessing superb bifunctional catalytic activity in base is reported, featured by low overpotentials of 131 and 283 mV to attain a current density of 500 mA cm −2 for HER and OER, respectively, outperforming most of non-noble bifunctional electrocatalysts reported hitherto. Particularly, this hybrid catalyst also displays an excellent overall water splitting activity, requiring low voltages of 1.561 and 1.663 V to attain 100 and 500 mA cm −2 with excellent durability in 1 m KOH, respectively. Most importantly, the catalyst is stable for >120 h, even when the current density is 500 mA cm −2 , which is prominently superior to IrO 2 (+) //Pt (−) coupled noble electrodes, and is among the very best bifunctional catalysts reported thus far. Detailed theoretical calculations reveal that the interfacial interaction between Fe 2 P and Co 2 N can further improve the H* binding energy at the iron sites.

Development of a Multi‐Element Copper‐Phosphorus‐Based Electrode for Efficient Hydrogen Evolution Reaction

“…[29][30][31][32] Additionally, because the sample was exposed to air, the peaks at 856.3 eV and 873.6 eV in Ni 2p and the peak at 133.4 eV in P 2p, (Figure 4 (c)), may be related to the formation of nickel phosphate or nickel oxide on the surface of Ni 12 P 5 . [33] In Figure 4 (b), the diffraction peak at 853.4 eV and 870.7 eV corresponds to the Ni 2p 3/2 peak and Ni 2p 1/2 peak formed by the spin-orbit splitting of Ni 2p with phosphorus in the form of chemical bonds, which can be attributed to the Ni-P bond. [34] Because it is significantly higher ChemistrySelect than the 852.8 eV of nickel, it can be inferred that there are more positive charges on Ni after binding.…”

In situmodification of metal electrode by integrated microbial corrosion and microbial mineralization usingShewanella oneidensisfor efficient oxygen evolution

“…The electrochemically active surface areas of the catalysts were investigated on the basis of C dl measurements. 49,50 Fig. 5d shows the C dl values of different M–S 2 /NF catalysts, calculated from the CV curves across the non-faradaic region at different sweep rates (Fig.…”

Surface and near-surface engineering design of transition metal catalysts for promoting water splitting

“…Zhou's group designed self-supported Fe 2 P/Co 2 N porous arrays as bifunctional catalysts for water splitting. 101 The synergetic cooperation between Fe 2 P and Co 2 N induces numerous Fe catalytic sites with suitable hydrogen adsorption free energy, resulting in superior catalytic activities with low overpotentials of 131 and 283 mV to attain a current density of 500 mA cm −2 for the HER and OER, respectively (Fig. 6a and b).…”