This review article summarises the progress, challenges and prospects of nanostructured cathode materials for lithium–sulfur batteries.

A unique nanostructure of 3D and vertically aligned and interconnected porous carbon nanosheets (3D‐VCNs) is demonstrated by a simple carbonization of agar. The key feature of 3D‐VCNs is that they possess numerous 3D channels with macrovoids and mesopores, leading to high surface area of 1750 m2 g−1, which play an important role in loading large amount of sulfur, while vertically aligned microporous carbon nanosheets act as the multilayered physical barrier against polysulfides anions and prevent their dissolution in the electrolyte due to strong adsorption during cycling process. As a result, the 3D hybrid (3D‐S‐VCNs) infiltered with 68.3 wt% sulfur exhibits a high and stable reversible capacity of 844 mAh g−1 at the current density of 837 mA g−1 with excellent Coulombic efficiency ≈100%, capacity retention of ≈80.3% over 300 cycles, and good rate ability (the reversible capacity of 738 mAh g−1 at the high current density of 3340 mA g−1). The present work highlights the vital role of the introduction of 3D carbon nanosheets with macrovoids and mesopores in enhancing the performance of LSBs.

The successful photo-catalyst library gives significant information on feature that affects photo-catalytic performance and proposes new materials. Competency is considerably significant to form multi-functional photo-catalysts with flexible characteristics. Since recently, two-dimensional materials (2DMs) gained much attention from researchers, due to their unique thickness-dependent uses, mainly for photo-catalytic, outstanding chemical and physical properties. Photo-catalytic water splitting and hydrogen (H2) evolution by plentiful compounds as electron (e−) donors is estimated to participate in constructing clean method for solar H2-formation. Heterogeneous photo-catalysis received much research attention caused by their applications to tackle numerous energy and environmental issues. This broad review explains progress regarding 2DMs, significance in structure, and catalytic results. We will discuss in detail current progresses of approaches for adjusting 2DMs-based photo-catalysts to assess their photo-activity including doping, hetero-structure scheme, and functional formation assembly. Suggested plans, e.g., doping and sensitization of semiconducting 2DMs, increasing electrical conductance, improving catalytic active sites, strengthening interface coupling in semiconductors (SCs) 2DMs, forming nano-structures, building multi-junction nano-composites, increasing photo-stability of SCs, and using combined results of adapted approaches, are summed up. Hence, to further improve 2DMs photo-catalyst properties, hetero-structure design-based 2DMs’ photo-catalyst basic mechanism is also reviewed.

Single‐atom catalysts (SAC) can boost the intrinsic catalytic activity of hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). However, the challenge remains due to the complex synthesis process and insufficient stability. A sustainable approach is applied to synthesizing SACs through laser irradiation and gaining mesoporous graphene oxide (MGO). The surface dangling bonds of nitrogen‐doped MGO (NMGO) extract metal atoms species from Co or Fe metal foams and convert them to SAC via an appropriate synthesis approach. Notably, the Co‐NMGO electrocatalyst requires low potentials of 146 mV to convey a current density of 10 mA cm−2 towards HER. Similarly, the Fe‐NMGO electrocatalyst offers an onset of 0.79 V towards ORR in acidic solution. The individual metal atoms are confirmed via aberration‐corrected scanning transmission electron microscopy, and X‐ray absorption near‐edge structure and extended X‐ray absorption fine structure. Density functional theory calculations by applying the grand canonical potential kinetics model revealed that Co‐NMGO shows the optimum free reaction energy of −0.17 eV at −0.1 V for HER, and Fe‐NMGO has less limiting potential than that of Co‐NMGO for ORR case. This work opens a new approach towards the synthesis of SAC and its mechanistic understandings.