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Hybrid materials, integrating the merits of individual components, are ideal structures for efficient oxygen evolution reaction (OER). However, the rational construction of hybrid structures with decent physical/electrochemical properties is yet challenging. Herein, a promising OER electrocatalyst composed of trimetallic metal-organic frameworks supported over S/N-doped carbon macroporous fibers (S/N-CMF@FexCoyNi1-x-y-MOF) via a cation-exchange strategy is delicately fabricated. Benefiting from the trimetallic composition with improved intrinsic activity, hollow S/N-CMF matrix facilitating exposure of active sites, as well as their robust integration, the resultant S/N-CMF@FexCoyNi1-x-y-MOF electrocatalyst delivers outstanding activity and stability for alkaline OER. Specifically, it needs an overpotential of 296 mV to reach the benchmark current density of 10 mA cm−2 with a small Tafel slope of 53.5 mV dec−1. In combination with X-ray absorption fine structure spectroscopy and density functional theory calculations, the post-formed Fe/Co-doped γ-NiOOH during the OER operation is revealed to account for the high OER performance of S/N-CMF@FexCoyNi1-x-y-MOF. Ministry of Education (MOE) Submitted/Accepted version X.W.L. acknowledges the funding support from the Ministry of Education of Singapore through the Academic Research Fund (AcRF) Tier-2 grant (MOE2019-T2-2-049).

Mn-based oxides have sparked extensive scientific interest for aqueous Zn-ion batteries due to the rich abundance, plentiful oxidation states, and high output voltage. However, the further development of Mn-based oxides is severely hindered by the rapid capacity decay during cycling. Herein, a two-step metal-organic framework (MOF)-engaged templating strategy has been developed to rationally synthesize heterostructured Mn 2 O 3 -ZnMn 2 O 4 hollow octahedrons (MO-ZMO HOs) for stable zinc ion storage. The distinctive composition and hollow heterostructure endow MO-ZMO HOs with abundant active sites, enhanced electric conductivity, and superior structural stability. By virtue of these advantages, the MO-ZMO HOs electrode shows high reversible capacity, impressive rate performance, and outstanding electrochemical stability. Furthermore, ex situ characterizations reveal that the charge storage of MO-ZMO HOs mainly originates from the highly reversible Zn 2+ insertion/extraction reactions.

Single-atom catalysts (SACs) are being pursued as economical electrocatalysts. However, their low active-site loading, poor interactions, and unclear catalytic mechanism call for significant advances. Herein, atomically dispersed Ni/Co dual sites anchored on nitrogen-doped carbon (a-NiCo/NC) hollow prisms are rationally designed and synthesized. Benefiting from the atomically dispersed dual-metal sites and their synergistic interactions, the obtained a-NiCo/NC sample exhibits superior electrocatalytic activity and kinetics towards the oxygen evolution reaction. Moreover, density functional theory calculations indicate that the strong synergistic interactions from heteronuclear paired Ni/Co dual sites lead to the optimization of the electronic structure and the reduced reaction energy barrier. This work provides a promising strategy for the synthesis of high-efficiency atomically dispersed dual-site SACs in the field of electrochemical energy storage and conversion. Ministry of Education (MOE) Submitted/Accepted version X.W.L. acknowledges the funding support from the Ministry of Education of Singapore through the Academic Research Fund (AcRF)Tier-2 grant (MOE2019-T2-2-049).

Mn-based oxides have sparked extensive scientific interest for aqueous Zn-ion batteries due to the rich abundance, plentiful oxidation states, and high output voltage. However, the further development of Mn-based oxides is severely hindered by the rapid capacity decay during cycling. Herein, a two-step metal-organic framework (MOF)-engaged templating strategy has been developed to rationally synthesize heterostructured Mn

Efficient electrocatalytic water splitting is one of the most effective ways to solve the global energy crisis. In this paper, we report on a novel self-assembled hierarchical structure of Co3O4/CoMoO4 grown in situ on a bare nickel foam. The unique, three-dimensional honeycomb-like Co3O4 pores were constructed from one-dimensional nanowires and coated on two-dimensional CoMoO4 nanosheets structures grown on nickel foam. The synthesis involved a step-wise solvothermal method followed by an annealing treatment. Benefiting from the synergistic effect of the hierarchical nanostructures, the materials had more reaction active sites and a smaller electron transfer impedance, and they exhibited excellent electrocatalytic performances for the HER and OER of 143 and 244 mV, respectively, at 10 mA cm−2 in an alkaline solution. Furthermore, the materials remained stable during the long electrolysis period, over 10 h, presenting promising application prospects in the field of electrocatalytic water splitting.

As a promising hydrogen production method, alkaline water electrolysis has the main disadvantage of high energy consumption. Although some electrodes prepared by hydrothermal synthesis have excellent performance, the cumbersome preparation process cannot meet the future application. Here, we fabricated the electrode with schistose stacked hemispherical structure by DC electroplating at high current density for a long time, subsequently, the composition of the electrode was changed by continuous redox reaction. The electrode combine the excellent hydrogen and oxygen evolution characteristics of Ni and Fe elements, and has a large specific surface area, which means that it can provide more active site in HER and OER, thus, the overpotential can be greatly reduced. The electrode has excellent performance of HER, with overpotential of 41 mV and 132 mV at current density of 10 and 100 mA cm−2, respectively, in 1 M potassium hydroxide solution. In OER, the overpotential is 270 mV at current density of 100 mA cm−2. In overall water splitting test, the electrode only needs 1.54 V to reach 10 mA cm−2. At the same time, the prepared electrodes have good stability, and the cell voltage increases by only 1.4% even at 300 mA cm−2 current density for 40 h.

A 3D hierarchical flower-like structure (HFs) constructed by 2D nanosheets was firstly prepared on Ti-based SnO2 electrode by hydrothermal method. The fabricated Ti/SnO2-Sb-HFs electrode was characterized in detail by SEM and XRD that reveal a denser surface layer and a smaller crystallite size rather than traditional Ti/SnO2-Sb electrode. Through in-depth investigation of electrochemical properties by CV, Voltammetric charge analysis, EIS and LSV, the results show that the Ti/SnO2-Sb-HFs electrode has a higher oxygen evolution potential, a lower charge transfer resistance and a larger electrochemical active surface area. Especially, the stability of the electrode is improved most obviously. The accelerated life of Ti/SnO2-Sb-HFs electrode can reach 149.5 min at current density of 1 A cm−2, which is 9.3 times as long as that of electrode without hierarchical flower-like structure. Moreover, Acid Red 73 was selected as simulated wastewater to evaluate the electrocatalytic oxidation ability of electrodes. The experiments showed that the removal rate of AR 73 and COD on Ti/SnO2-Sb-HFs electrode can reach 98.7% and 83.9% respectively after 5 h, which was superior to that of Ti/SnO2-Sb electrode (91.5% and 72.6%).

To reduce the dust pollution caused by the construction industry, calcium magnesium acetate (CMC), and glycerin as the primary raw materials, sodium dodecyl benzene sulfonate (SDBS) as the ...