Two-dimensional materials have gained immense attention for technological applications owing to their characteristic properties. MXene is one of the fast-growing family of 2D materials that exhibits remarkable physiochemical properties that cater numerous applications in the field of energy and storage. This review comprises the significant advancement in the field of 2D MXene and discusses the evolution of the design, synthetic strategies, and stability. In addition to illuminating the state-of-the-art applications, we discuss the challenges and limitations that preclude the scientific fraternity from realizing functional MXene with controlled structures and properties for renewable clean energy conversion and storage applications.

In this present study, we report the synthesis of Au nanodots on α-Fe₂O₃@reduced graphene oxide (RGO) based hetero-photocatalytic nanohybrids through a chlorophyll mediated photochemical synthesis. In this process, chlorophyll induces a rapid reduction (30 min) of Au³⁺ions to Au° metallic nanodots on α-Fe₂O₃@RGO surface under sunlight irradiation. The nucleation growth process, photo-induced electron-transfer mechanism and physico-chemical properties of the Au@α-Fe₂O₃@RGO ternary nanocomposites were systematically studied with various analytical techniques. This novel photochemical synthesis process is a cost-effective, convenient, surfactant-less, and scalable method. Moreover, the prepared ternary nanocomposites enhanced catalytic activity as compared to pure α-Fe₂O₃and α-Fe₂O₃@RGO. The advantages and synergistic effect of Au@α-Fe₂O₃@RGO exhibit, (i) a broader range of visible-light absorption due to visible light band gap of α-Fe₂O₃, (ii) lower recombination possibility of photo-generated electrons and holes due to effect of Au and (iii) faster electron transfer due to higher conductivity of RGO. Therefore, the prepared Au@α-Fe₂O₃@RGO hetero-photocatalytic nanohybrids exhibited a remarkable photocatalytic activity, thus enabling potential active hetero-photocatalyst for industrial and environmental applications.

Pure self-assembled L-cysteine stabilized covellite nanoplates (CuS@L-Cys NPs) with the best control over size, phase purity structure, morphology, and electrochemical properties were synthesized using a facile, template-free hydrothermal route. The effects of temperature (100–180 °C), reaction time (8–24 h), pH of reaction medium (7–14), concentration of base (0.1–2.4 mL NH₃) and concentration of thiourea (1–4 mmol) on the morphologies of CuS@L-Cys nanoplates were studied. The photocatalytic performance of CuS@L-Cys NPs under visible light was studied using methyl orange (MO) as a model dye. CuS@L-Cys NPs were reused successfully for the photodegradation of dye due to the recycling ability of CuS@L-Cys NPs. The hydroxyl radicals (˙OH) generated by CuS@L-Cys NPs were detected using terephthalic acid (TA) as a probe molecule through the photoluminescence (PL) technique. The successful capping of L-Cys on the surface of CuS NPs was confirmed by FTIR spectroscopy. The BET surface areas of the hexagonal CuS@L-Cys NPs and oblong CuS@L-Cys NPs were measured to be 11.87 and 5.66 m² g⁻¹, respectively. The optical band gaps of the hexagonal CuS@L-Cys NPs (2.0 eV) and oblong CuS@L-Cys NPs (2.04 eV) were determined according to direct bandgap calculations. These results support the presence of hexagonal CuS@L-Cys NP catalysts as efficient accelerators of the photodegradation of MO. Furthermore, the L-cysteine (L-Cys) protective layer could efficiently alleviate the photocorrosion of CuS, giving rise to excellent stability. The high photocatalytic activity of the hexagonal CuS@L-Cys NPs can be ascribed to the reduction of photoinduced electron–hole pair recombination and high specific surface area, as confirmed by BET for other representative samples.