The design of cost-effective electrocatalysts is critical for advancing sustainable energy technologies, particularly for key reactions like the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) in water electrolyzers and metal-air batteries. Cobalt pentlandite (CNFS) has emerged as a promising candidate, offering high conductivity, stability, and the advantage of using abundant elements. In this study, density functional theory (DFT) calculations reveal that tungsten (W) doping in CNFS, combined with an increased concentration of sulfur vacancies, can effectively shift the d-band center downward enhancing metal-sulfur orbital hybridization. These modifications facilitate the desorption of oxygen intermediate while maintaining structural integrity. Additionally, the engineering of this material with a hollow architecture further increases active site exposure, significantly improving catalytic activity. As a result of this multifaceted approach, the W-doped CNFS catalyst achieves a remarkably low OER overpotential of 241 mV at 50 mA cm(-)2, alongside enhanced ORR activity. Furthermore, the catalyst demonstrates excellent performance in rechargeable zinc-air batteries (ZABs), achieving a peak power density of 100 mW cm(-)2 and sustaining over 650 h of cycling at 4 mA cm(-)2. Overall, this study presents a viable strategy for improving ZAB performance and reducing costs by utilizing efficient and cost-effective metal sulfides with a cobalt pentlandite structure.

Maintaining the surface structure stability of LiCoO2 (LCO) during rapid charge-discharge processes (>5C) and under high-voltage conditions (>4.2 V) is challenging due to interfacial side reactions, cobalt dissolution, and oxygen redox activity at deeply delithiated states, all of which contribute to performance degradation. Herein, different from traditional surface coating methods, we report a water-mediated strategy that modifies the surface architecture of LCO, creating a passivating layer to inhibit surface degradation and enhance cycling stability under fast charging conditions. The surface etching of LCO by H2O is accompanied by a concurrent Li+/H+ cation exchange, which passivates surface oxygen with H+ ions, thereby enhancing both the hydrophobicity and structural stability. Consequently, the modified LCO exhibits superior capacity retention, which is 2.5 times that of the pristine LCO, after 100 cycles at a current density of 1000 mA g-1 (∼6C at 4.5 V). Even at an elevated temperature of 45 °C, it maintains impressive cycling stability at a current density of 500 mA g-1 (∼3C), as demonstrated in practical full-cell configurations. Investigation with multiple samples confirmed that the water-mediated strategy demonstrated broad applicability. We emphasize that the water-mediated modification of the surface architecture on cathode materials offers significant insights into enhancing the stability of high-energy-density lithium-ion batteries (LIBs).

Maximizing the utilization of photogenerated electrons and holes to drive the coupling reaction of hydrogen evolution with selective value-added organic synthesis holds great potential for more efficient exploitation of solar energy. Herein, the interstitial boron-doped CdS is synthesized by taking SiO2 as a template as well as the adsorption sites of boric acid, which contributes to the boron doping and induces the reinforced Cd & horbar;Se bonding for enhancing the interfacial interaction with co-catalyst MoSe2. Thus, the interfacial Cd & horbar;Se bond with more electron localization provides rapid channels at the atomic level for accelerating the charge transfer with a lower energy barrier, achieving the efficient hydrogen evolution and high selectivity pyruvic acid synthesis concurrently. This work provides a new perspective in avoiding the use of sacrificial agents uneconomically and producing green hydrogen with high-value-added chemicals simultaneously. The interstitial boron-doped CdS induces the reinforced Cd & horbar;Se bonding for enhancing the interfacial interaction with co-catalyst MoSe2, which provides the foundation for maximizing the utilization of photogenerated electrons and holes simultaneously, thus achieving the efficient hydrogen evolution and high selectivity pyruvic acid synthesis concurrently. image

The prolonged hot electron lifetimes induced by hollow-structured ZnIn 2 S 4 for boosting the kinetics of hot electron driven photocatalytic reactions.

Construction of direct Z-scheme photocatalytic heterojunctions with an internal electric field has been proposed as an outstanding method to achieve efficient utilization of solar energy for photocatalytic overall water-splitting. In this work, the properties of van der Waals (vdW) heterojunctions formed by group-IV mono-chalcogenides (MXs) (M = Ge, Sn; X = S, Se, Te) and MoS2 are systematically studied by first-principles calculations, including the vdW binding energy, the direction of an internal electric field and the electronic structure. The results predict that GeS/MoS2, GeSe/MoS2 and SnS/MoS2 vdW heterojunctions are potential direct Z-scheme water-splitting photocatalysts with appropriate band alignments, a wide light absorption range and low effective charge-carrier mass. Furthermore, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) activities of the heterojunctions as photocatalysts are predicted. The results indicate that SnS/MoS2 with the Sn vacancy has a low Gibbs free energy of the HER (0.06 eV), and MoS2 with the S edge can offer OER active sites. This study provides a theoretical basis for the further design and preparation of a new two-dimensional overall water-splitting photocatalyst, which is conducive to the development of efficient two-dimensional photocatalysts in the field of clean energy.

Two-dimensional vanadium diselenide (VSe2) has attracted extensive interest due to its room-temperature ferromagnetism with many potential applications. However, the intrinsic ferromagnetic (FM) ordering is confined to monolayers, which hinders their practical use because of fabrication difficulty. In this work, the effect of strain on magnetic properties of few-layer 1T-VSe2 is studied based on first-principles calculations. Spin-polarized density functional theory calculations indicate that the monolayer is intrinsic FM, while the bilayer, trilayer, and quadlayer 1T-VSe2 are intralayer FM but interlayer anti-ferromagnetic (AFM). The results predict that few-layer 1T-VSe2 can undergo a prominent magnetic transition from AFM to FM and an enhancement of magnetic moment by introducing in-plane tensile strain above 2%. A universal model is proposed to explain the enhanced FM that the structural deformation leads to symmetry breaking of the interlayer orbital hybridization, thus inducing FM of the whole system through an intralayer super-exchange effect. It is further verified on broader materials, including manganese and vanadium chalcogenides. This study provides a feasible route for achieving and modulating FM in two-dimensional materials, which have great significance in practical spintronic devices.