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Renewable and low-cost biomass is an ideal sustainable alternative to petroleum-based resources, but producing biomass-based carbon electrode with high performances remains a challenge. Herein, we propose a facile self-assembly strategy to fabricate a biomass-derived N, S co-doping carbon electrode from lignosulfonate without any activation or template process. Taking advantage of the coordination between Fe ions and lignosulfonate, the resultant carbon exhibits a spherical structure with abundant graphitized nanosheets, leading to a high specific surface area with rational pore structure, which are beneficial to the electron/ion transport and storage. The high contents of doping N (8.47 wt%) and S (2.56 wt%) significantly boost the electrochemical performances. As a supercapacitor electrode, the carbon material displays high specific capacitance of 390 F g−1, excellent cycling stability and high energy density of 14.7 W h kg−1 at a power density of 450 W kg−1. This study provides a potential strategy for synthesizing cost-effective heteroatom-doped carbon materials from biomass with abundant functional groups and heteroatom sources, such as chitosan, collagen, and gelatin. Graphical Abstract

Organic/inorganic metal halide perovskites attract substantial attention as key materials for next-generation photovoltaic technologies due to their potential for low cost, high performance, and solution processability. The unique properties of perovskites and the rapid advances that have been made in solar cell performance have facilitated their integration into a broad range of practical applications, including tandem solar cells, building-integrated photovoltaics, space applications, integration with batteries and supercapacitors for energy storage systems, and photovoltaic-driven catalysis. In this Review, we outline notable achievements that have been made in these photovoltaic-integrated technologies. Outstanding challenges and future perspectives for the development of these fields and potential next-generation applications are discussed.

Photosensitized heterogeneous CO2 reduction (PHCR) has emerged as a promising means to convert CO2 into valuable chemicals, however, challenged by the relatively low carbonaceous product selectivity caused by the competing hydrogen evolution reaction (HER). Here, we report a PHCR system that couples Ru(bpy)32+ photosensitizer with {001} faceted LiCoO2 nanosheets photocatalyst to simultaneously yield 21.2 and 722 µmol·g−1·h−1 of CO, and 4.42 and 108 µmol·g−1·h−1 of CH4 under the visible light and the simulated sunlight irradiations, respectively, with completely suppressed HER. The experimental and theoretical studies reveal that the favored CO2 adsorption on the exposed Li sites on {001} faceted LiCoO2 surface is responsible for the completely suppressed HER.

Defect engineering involves the manipulation of the type, concentration, mobility or spatial distribution of defects within crystalline structures and can play a pivotal role in transition metal oxides in terms of optimizing electronic structure, conductivity, surface properties and mass ion transport behaviors. And of the various transition metal oxides, titanium-based oxides have been keenly investigated due to their extensive application in electrochemical storage devices in which the atomic-scale modification of titanium-based oxides involving defect engineering has become increasingly sophisticated in recent years through the manipulation of the type, concentration, spatial distribution and mobility of defects. As a result, this review will present recent advancements in defect-engineered titanium-based oxides, including defect formation mechanisms, fabrication strategies, characterization techniques, density functional theory calculations and applications in energy conversion and storage devices. In addition, this review will highlight trends and challenges to guide the future research into more efficient electrochemical storage devices. This work reviews the recent advances in defect-engineered Ti-based oxides, including the mechanism of defect formation, fabrication strategies, the characterization techniques, density functional theory calculations and the applications in energy conversion and storage.

In this work, we present a facile yet effective method to prepare boron-doped, highly reduced electrochemical graphene oxide (B-rEGO) using electrochemical oxidation coupled with high-temperature thermal reduction. We first fabricated EGO from natural graphite powder in different concentrations of sulfuric acid electrolytes in a packed-bed reactor and found that the 12 M acid could produce EGO with the highest level of oxidation. To introduce heteroatom doping (non-metallic boron), sufficient boric acid was added to the sulfuric acid electrolyte for electrochemical reactions whereby the boron-doped graphene precursor could be formed, namely tetraborate anion intercalated EGO compounds, and it could transform into B-rEGO by annealing at 900 °C for 3 h under Ar gas. We found that the B-rEGO was highly defective as well as effectively deoxygenated and contained 0.21 at.% of boron. The as-prepared B-rEGO is used as an active material in sodium ion battery anodes, delivering a good capacity of 129.59 mAh g−1 at the current density of 100 mA g−1 and long-term cyclic stability which could retain 100.20 mA g−1 after 800 cycles at 500 mA g−1.

The development of a facile method to construct a high-performance electrode is of paramount importance to the application of alkaline water electrolysis. Here, we report that the activity of nickel foam (NF) towards the oxygen evolution reaction (OER) can be enhanced remarkably through simple immersion in a ferric nitrate (Fe(NO3)3) solution at room temperature. During this immersion process, the oxidation of the NF surface by NO3− ions increases the near-surface concentrations of OH− and Ni2+, which results in the in situ deposition of a highly active amorphous Ni-Fe hydroxide (a-NiFeOxHy) layer. Specifically, the OER overpotential of the NF electrode decreases from 371 mV (bare NF) to 270 mV (@10 mA·cm−2 in 0.1 M KOH) after immersion in a 20 mM Fe(NO3)3 solution for just 1 min. A longer immersion time results in further increased OER activity (196 mV@10 mA·cm−2 in 1 M KOH). The overall water splitting properties of the a-NiFeOxHy@NF electrode were evaluated using a two-electrode configuration. It is worth noting that the current density can reach 25 mA·cm−2 in 6 M KOH at an applied voltage of 1.5 V at room temperature.

The emergence of nanostructured and composite materials has resulted in significant advancements in energy conversion and storage. The design and development of low-dimensional nanomaterials and composites include photocatalysts for photoelectrochemical devices for solar fuel production; semiconductor nanomaterials for new-generation solar cells, high specific surface area electrodes for efficient energy storage systems including batteries and supercapacitors, and nanocatalysts for increased triple phase boundaries in fuel cells, among others.

Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step thermochemical H2O splitting. Herein, an analogue of La1−xCa x MnO3 perovskite was systematically investigated as a catalyst for thermochemical H2 evolution. The Ca doping level (x = 0.2, 0.4, 0.6, 0.8) and re-oxidation temperature were comprehensively optimized for the improvement of catalytic performance. According to our experimental results, La0.6Ca0.4MnO3 perovskite displayed the highest yield of H2 at the re-oxidation temperature of 900 °C and the obtained H2 production was ~ 10 times higher than that of the benchmark ceria catalyst under the same experimental condition. More importantly, La0.6Ca0.4MnO3 perovskite catalyst exhibited impressive cyclic stability in repetitive O2 and H2 test.