Single-atom catalysts (SACs) with high catalytic activity as well as great stability are demonstrating great promotion in electrocatalytic energy conversion, which is also a big challenge to achieve. Herein, we proposed a facile synthetic strategy to construct nickel-iron bimetallic hydroxide nanoribbon stabilized single-atom iridium catalysts (Ir-NiFe-OH), where the nickel-iron hydroxide nanoribbon not only can serve as good electronic conductor, but also can well stabilize and fully expose single-atom sites. Adopted as catalyst for urea oxidation reaction (UOR), it exhibited excellent UOR performance that it only needed a low operated potential of 1.38 V to achieve the current density of 100 mA·cm⁻². In-situ Fourier transform infrared spectroscopy, X-ray absorption spectrum, and density functional theory calculations proved that Ir species are active centers and the existence of both Ni and Fe in the local structure of Ir atom can optimize the d-band center of Ir species, promoting the adsorption of intermediates and desorption of products for UOR. The hydrogen evolution reaction (HER)/UOR electrocatalytic cell demanded voltages of 1.46 and 1.50 V to achieve 50 and 100 mA·cm⁻², respectively, which demonstrated a higher activity and better stability than those of conventional catalysts. This work opens a new avenue to develop catalysts for UORs with boosted activity and stability.

Lithium-sulfur (Li-S) battery has attracted extensive attention because of its ultrahigh theoretical energy density and low cost. However, its commercialization is seriously hampered by its short cycling life, mainly due to the shuttle of soluble lithium polysulfides (LiPSs) and poor rate capability due to sluggish reaction kinetics. Although significant efforts have been devoted to solving the problems, it is still challenging to simultaneously address all the issues. Herein, titanium nitride hollow multishelled structure (TiN HoMS) sphere is designed as a multi-functional catalytic host for sulfur cathode. TiN, with good conductivity, can effectively catalyze the redox conversion of S and LiPSs, while its surficial oxidation passivation layer can strongly anchor LiPSs. Besides, HoMS enables TiN nanoparticle subunits to expose abundant active sites for anchoring and promoting conversion of LiPSs, while the multiple shells provide physical barriers to restrict the shuttle effect. In addition, HoMS can buffer the volume expansion of sulfur and shorten the charge transport pathway. As a result, the sulfur cathode based on triple-shelled TiN HoMS exhibits an initial specific capacity of 1016 mAh·g⁻¹ at a high sulfur loading of 2.8 mg·cm⁻² and maintains 823 mAh·g⁻¹ after 100 cycles. Moreover, it shows a four times higher specific capacity than the one without TiN host at 2 C.

Fabricating single-atom catalysts (SACs) with high catalytic activity as well as great stability is a big challenge. Herein, we propose a precise synthesis strategy to stabilize single atomic ruthenium through regulating vanadium defects of nickel vanadium layered double hydroxides (NiV-LDH) ultrathin nanoribbons support. Correspondingly, the isolated atomically Ru doped NiV-LDH ultrathin nanoribbons (NiVRu-R) were successfully fabricated with a super-high Ru load of 12.8 wt.%. X-ray absorption spectrum (XAS) characterization further confirmed atomic dispersion of Ru. As catalysts for electrocatalytic hydrogen evolution reaction (HER) in alkaline media, the NiVRu-R demonstrated superior catalytic properties to the commercial Pt/C. Moreover, it maintained exceptional stability even after 5,000 cyclic voltammetry cycles. In-situ XAS and density functional theory (DFT) calculations prove that the Ru atomic sites are stabilized on supports through forming the Ru–O–V structure, which also help promote the catalytic properties through reducing the energy barrier on atomic Ru catalytic sites.

Solar thermal interfacial water evaporation is proposed as a promising route to address freshwater scarcity, which can reduce energy consumption and have unlimited application scenarios. The large semiconductor family with controllable bandgap and good chemo-physical stability are considered as good candidates for photo-evaporation. However, the evaporation rate is not satisfactory because the rational control of nano/micro structure and composition is still in its infancy stage. Herein, by systemically analyzing the photo-thermal evaporation processes, we applied the hollow multishelled structure (HoMS) into this application. Benefiting from the multishelled and hierarchical porous structure, the light absorption, thermal regulation, and water transport are simultaneously optimized, resulting in a water evaporation rate of 3.2 kg·m⁻²·h⁻¹, which is among the best performance in solar-vapour generation. The collected water from different water resources meets the World Health Organization standard for drinkable water. Interestingly, by using the CuO/Cu₂O system, reactive oxygen species were generated for water disinfection, showing a new route for efficient solar-vapour generation and a green way to obtain safe drinking water.

Hollow microspheres of two bismuth oxychlorides, BiOCl and Bi₂₄O₃₁Cl₁₀, were successfully synthesized using carbonaceous microsphere sacrificial templates. The phase evolution from BiOCl to Bi₂₄O₃₁Cl₁₀ was easily realized by heating the former at 600 ℃. With a uniform diameter of about 200 nm, an average shell thickness of 40 nm, and basic nanosheets of < 20 nm, the hollow microspheres of both BiOCl and Bi₂₄O₃₁Cl₁₀ showed high visible light photocatalytic activity towards the degradation of Rhodamine B (RhB). Besides the effective photosensitization process and efficient photointroduced carrier separation, the high photocatalytic activity was believed to result from their hollow-structure-dependent large visible light absorption. Moreover, as a chlorine-deficient analogue, the Bi₂₄O₃₁Cl₁₀ hollow spheres possessed a narrower band gap, more dispersive band structure, and higher photocarrier conversion efficiency, which further helped them to exhibit better photocatalytic activity.