Publications

It is highly desirable to develop a simple, fast and straightforward method to boost the alkaline water oxidation of metal oxide catalysts. In this communication, we report our recent finding that the generation of amorphous Co-borate layer on Co₃ O₄ nanowire arrays supported on Ti mesh (Co₃ O₄ @Co-Bi NA/TM) leads to significantly boosted OER activity. The as-prepared Co₃ O₄ @Co-Bi NA/TM demands overpotential of 304 mV to drive a geometrical current density of 20 mA cm^-2 in 1.0 M KOH, which is 109 mV less than that for Co₃ O₄ NA/TM, with its catalytic activity being preserved for at least 20 h. It suggests that the existence of amorphous Co-Bi layer promotes more CoO_x (OH)_y generation on Co₃ O₄ surface.

Owing to the high power density and ultralong cycle life, supercapacitors represent an alternative to electrochemical batteries in energy storage applications. However, the relatively low energy density is the main challenge for supercapacitors in the current drive to push the entire technology forward to meet the benchmark requirements for commercialization. To effectively solve this issue, it is crucial to develop electrode materials with excellent electrochemical performance since the electrode used is closely related to the specific capacitance and energy density of supercapacitors. With the unique structure, compositional flexibility, and inherent oxygen vacancy, perovskite oxides have attracted wide attention as promising electrode materials for supercapacitors. In this review, we summarize the recent advances in perovskite oxides as electrode materials for supercapacitors. Firstly, the structures and compositions of perovskite oxides are critically reviewed. Following this, the progress in various perovskite oxides, including single perovskite and derivative perovskite oxides, is depicted, focusing on their electrochemical performance. Furthermore, several optimization strategies (i.e., modulating the stoichiometry of the anion or cation, A-site doping, B-site doping, and constructing composites) to improve their electrochemical performance are also discussed. Finally, the significant challenges facing the advancement of perovskite oxide electrodes for supercapacitor applications and future outlook are proposed.

Electrocatalytic nitrogen reduction reaction (NRR) enabled by introducing Ti³⁺ defect sites into TiO₂ through a doping strategy has recently attracted widespread attention. However, the amount of Ti³⁺ ions is limited due to the low concentration of dopants. Herein, we propose Ti₂O₃ nanoparticles as a pure Ti³⁺ system that performs efficiently toward NH₃ electrosynthesis under ambient conditions. This work has suggested that Ti³⁺ ions, as the main catalytically active sites, significantly increase the NRR activity. In an acidic electrolyte, Ti₂O₃ achieves extraordinary performance with a high NH₃ yield and a Faradaic efficiency of 26.01 μg h^-1 mg^-1 cat. and 9.16%, respectively, which are superior to most titanium-based NRR catalysts recently reported. Significantly, it also demonstrates a stable NH₃ yield in five consecutive cycles. Theoretical calculations uncovered that the enhanced electrocatalytic activity of Ti₂O₃ originated from Ti³⁺ active sites and significantly lowered the overpotential of the potential-determining step.

Abstract Hematite (α‐Fe 2 O 3 ) semiconductor is an abundant and non‐toxic catalyst for different (photo)electrochemical reactions. In this work, a selective p‐nitrophenol sensor was developed by fabricating a thin‐layer of a glassy carbon electrode (GCE) with 5% nafion coating binders onto α‐Fe 2 O 3 thin film synthesized by a simple and inexpensive process. High sensitivity including linear dynamic range, long‐term stability, and enhanced electrochemical performance towards p‐nitrophenol were achieved by a reliable current‐voltage method. A linear calibration curve was observed over a wide range of p‐nitrophenol concentrations. Very low detection limit (0.6±0.02 nM), good limit of quantification (2.0 nM) and high sensor sensitivity ( K =74.1 μA⋅cm −2 ) are calculated based on noise to signal ratio of ∼3 N/S. Very importantly, the detection range covers over 7 orders of magnitude concentrations, from nM to mM. Figures of merits are comparable with best reported results whilst using a very simple device configuration. We show that hematite is an excellent material for the development of chemical sensors to detect hazardous compounds for environmental safety in a broad scale of concentrations.

Inverted planar perovskite solar cells (PSCs) have intrigued great promise in negative hysteresis, simple fabrication process, and flexible substrate implementation, in which the shared hole transport materiel is NiO x . However, the low‐temperature solution processing of the NiO x film is usually accompanied by defect formation, which deteriorates the perovskite quality and device performance. Meanwhile, the energy‐level offset between the NiO x and perovskite films is relatively large, limiting the interfacial charge transport. To suppress those setbacks, a defect‐free monolayer graphene sheet is transferred onto the NiO x film surface as a template for van der Waals epitaxial growth of perovskite films for the first time, leading to enhancing crystallinity with a large grain size of perovskite layer, 0.20 eV energy level offset drop, and accelerating charge transfer for the devices. Finally, the power conversion efficiency of 19.21% without hysteresis is achieved, exceeding 18.35% of the control device.

Nickel-borate nanosheets array on titanium mesh (Ni-Bi NA/TM) was derived from NiSe₂ nanosheets array on titanium mesh (NiSe₂ NA/TM) by electrochemical transformation. As a three-dimensional electrode, Ni-Bi NA/TM exhibited high catalytic activity toward the oxygen evolution reaction and required a low overpotential of 430 mV at 10 mA cm^-2 in 0.1 m potassium borate (pH 9.2), with outstanding long-term stability and high turnover frequency.