As an alternative for depleting fossil fuel energy, hydrogen economy desires low-cost and efficient hydrogen production from water splitting. In order to explore a cheap, abundant, active, and durable catalyst for the electrocatalytic hydrogen evolution reaction (HER), two-dimensional (2D) ceria nanosheets are produced through a thermal decomposition exfoliation method from CeCO 3 OH with a layer-stacked structure. The additional cobalt dopant promotes formation of oxygen vacancies in ceria nanosheets and, in turn, optimizes hydrogen binding/water dissociation and increases the active sites. As a result, the 2D Codoped CeO 2 nanosheets exhibit an excellent catalytic performance in alkaline HER such that the overpotential is as low as 132 and 215 mV to deliver a high current density of 100 and 500 mA cm −2 , respectively, outperforming Pt. Such 2D Co-doped CeO 2 nanosheets are also durable HER electrocatalysts, as the activity loss during an extended period of operation is nearly negligible.

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Hydrogen economy is one of the most promising candidates to replace the current energy system on depleting fossil fuels. As a clean and sustainable way to produce hydrogen, electrocatalytic water splitting attracts ever-increasing interest from the research community. Although the wide application of platinum group metal (PGM) catalysts is limited because of the scarcity and high cost toward hydrogen evolution reaction (HER), the non-PGM electrocatalysts usually suffer from unsatisfactory activity and poor durability. In this work, we report an active and durable V-doped Ni5P4 electrocatalyst that can be used for all-pH HER. Particularly, V–Ni5P4 has an HER activity that is comparable to that of Pt in preferred alkaline media, with overpotentials as low as 13 mV and 295 mV at current densities of 10 and 1000 mA cm–2, respectively. The low-cost V–Ni5P4 that enables ultrahigh current density (i.e., at the level of A cm–2) would be of great interest to the hydrogen production industry.

Dendrite growth has been severely impeding the implementation of sodium (Na) metal batteries, which is regarded as one of the most promising candidates for next-generation highenergy batteries. Herein, SnO 2 quantum dots (QDs) are homogeneously dispersed and fully covered on a 3D carbon cloth scaffold (SnO 2 −CC) with high affinity to molten Na, given that SnO 2 spontaneously initiates alloying reactions with Na and provides low nucleation barrier for Na deposition. Molten Na can be rapidly infused into the SnO 2 −CC scaffold as a free-standing anode material. Because of the affinity between SnO 2 and Na ion, SnO 2 QDs can effectively guide Na nucleation and attains sitedirected dendrite-free Na deposition when combined with the 3D CC scaffold. This electrochemically stable anode enables almost 400 cycles at ultrahigh current density of 20 mA cm −2 in Na symmetric battery and delivers superior cycling performance and reversible rate capability in Na−Na 3 V 2 (PO 4 ) 3 full batteries.

CoOOH nanosheets synthesized by an in situ electrochemical anion-oxidation strategy were used as anodic catalysts in a hybrid water electrolyzer.