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• Multitude advances were found for V-rich Bi 2 S 3 nanowire than pristine Bi 2 S 3 photoelectrode. • V-rich Bi 2 S 3 nanowires achieve excellent photocurrent density for water splitting under visible light. • Deep insights on how the V-rich feature affects the PEC performance of Bi 2 S 3. Bi 2 S 3 is a n-type (negative type) semiconductor that has a narrow band gap and an ideal band edge position for hydrogen generation. However, high charge recombination rate, low photoelectrochemical (PEC) efficiency and poor stability are of major concerns of Bi 2 S 3 as a photoelectrode. Herein, we report an efficient Vanadium-rich Bi 2 S 3 nanowires (atomic ratio of V to Bi is 1/22) that have been prepared on fluorine-doped tin oxide (FTO) substrate by an in-situ solution-processed reaction with BiVO 4 film as precursor. The resulting V-rich photoelectrode demonstrates notably high charge separation efficiency and fast charge transport with respect to pristine Bi 2 S 3 nanowires. As a result, the photocurrent density of ca. 10 mA·cm−2 at -0.2 V vs Ag/AgCl is obtained under visible light illumination. In addition, V-rich Bi 2 S 3 generates IPCE (incident photocurrent-to-current conversion efficiency) of 50% at 460 nm and 45% at 760 nm, demonstrating a 2.0 and 2.8-fold increase, respectively, when compared with pristine Bi 2 S 3. This enhancement is probably due to increased light absorption, less charge recombination, and faster charge transfer. More importantly, in contrast to pristine Bi 2 S 3 sample that suffers detrimental photocorrosion in sulfide containing electrolyte, V-rich Bi 2 S 3 nanowires retain 84.6% of its initial photocurrent over the course of 1 h. These findings are expected to shed light on engineering high-performance and robust metal sulfide materials for photoelectrochemical application. [ABSTRACT FROM AUTHOR]

• A facile strategy to fabricate NiCo 2 Se 4 /NiCoS 4 heterostructure is developed. • NiCo 2 Se 4 /NiCoS 4 exhibited superior OER performance to IrO 2. • NiCo 2 Se 4 /NiCoS 4 showed excellent performance in water splitting and Zn-air battery. • It paves a path for preparing low cost and efficient catalysts with multifunctionalities. Rational design and constructing multifunctional electrocatalysts featuring with low cost and high efficiency is critical for promoting the implement of sustainable energy devices such as water splitting and zinc air batteries. Herein, we report a facile means to prepare a selenide/sulfide hetero-structured NiCo 2 Se 4 /NiCoS 4 catalyst for oxygen evolution reaction (OER), hydrogen evolution reaction (HER), overall water splitting (OWS), and Zn-air batteries (ZABs). The NiCo 2 Se 4 /NiCoS 4 heterostructure showed excellent OER and HER performance, evidenced by the small overpotential of 248 mV and 180 mV @ 10 mA cm−2 for OER and HER, and superior long-term stability to the benchmark IrO 2 and Pt/C catalyst for OER and HER, respectively. It also exhibited a potential of 1.660 V @ 10 mA cm−2 in the practical OWS test, close to the Pt/C + IrO 2 catalyst. Furthermore, when employed as air-cathode catalyst for ZABs, the NiCo 2 Se 4 /NiCoS 4 modified battery exhibited the narrow charge-discharge voltage gap of 0.98 V @ 50 mA cm−2 and a maximal specific capacity of 693.17 mA h g−1, outperforming the IrO 2 counterpart. Such excellent performance can be attributed to the advantageous structural merit of the NiCo 2 Se 4 nanoflowers, and especially the heterostructure interfaces created in NiCo 2 Se 4 /NiCoS 4 , which significantly boosted the catalytic synergistic effects. This study can offer a new avenue to design and prepare abundant-element-based cost effective, efficient and durable electrocatalysts with multifunctionalities that hold great promises to be applied in electrochemical devices. Image, graphical abstract [ABSTRACT FROM AUTHOR]