Solar water splitting provides a promising path for sustainable hydrogen production and solar energy storage. In recent times, metal−organic frameworks (MOFs) have received considerable attention as promising materials for diverse solar energy conversion applications. However, their photocatalytic performance is poor and rarely explored due to rapid electron− hole recombination. Herein, we have developed a material MOF@rGO that exhibits highly enhanced visible-light photocatalytic activity. A real-time investigation reveals that a strong π−π interaction between MOF and rGO is responsible for efficient separation of electron−hole pairs, and thereby enhances the photocatalytic hydrogen production activity. Surprisingly, MOF@rGO showed ∼9.1-fold enhanced photocatalytic hydrogen production activity compared to that of pristine MOF. In addition, it is worth mentioning here that remarkable apparent quantum efficiency (0.66%) is achieved by π−π interaction mediated charge carrier separation.

Conductive inks are a recent progress in electronics and have a promising future applications in flexible electronics and smart applications. In this review we tried to focus on a particular conductive ink, based on copper nanoparticles. Although wide research is being done all over the world, few complications are yet to be solved with perfection. We tried to focus on some of the complications involved in the synthesis and their various applications in the different fields of science. Conductive inks have promising applications in the present trend of science and technology. The main intention behind this review is to list out some of the best methods to synthesize copper nanoparticles according the category of synthesizing them. We chose copper nanoparticles synthesis and preparation of conductive inks because copper is a very abundant material possessing high conductivity (after silver), it has huge potential to replace expensive conductive inks made of silver, graphene, CNTs etc. The reason behind insisting on copper is also due to its properties such as ductility, malleability, thermal dissipation agent, possess anti microbial nature etc. In this review, we have listed out some of the best methods of synthesizing copper conductive ink and their usage in various printing techniques. Different methods of sintering for obtained conductive patterns are also included.

The photoelectrochemical (PEC) approach is attractive as a promising route for the nitrogen reduction reaction (NRR) toward ammonia (NH3) synthesis. However, the challenges in synergistic management of optical, electrical, and catalytic properties have limited the efficiency of PEC NRR devices. Herein, to enhance light‐harvesting, carrier separation/transport, and the catalytic reactions, a concept of decoupling light‐harvesting and electrocatalysis by employing a cascade n+np+‐Si photocathode is implemented. Such a decoupling design not only abolishes the parasitic light blocking but also concurrently improves the optical and electrical properties of the n+np+‐Si photocathode without compromising the efficiency. Experimental and density functional theory studies reveal that the porous architecture and N‐vacancies promote N2 adsorption of the Au/porous carbon nitride (PCN) catalyst. Impressively, an n+np+‐Si photocathode integrating the Au/PCN catalyst exhibits an outstanding PEC NRR performance with maximum Faradaic efficiency (FE) of 61.8% and NH3 production yield of 13.8 µg h–1 cm–2 at −0.10 V versus reversible hydrogen electrode (RHE), which is the highest FE at low applied potential ever reported for the PEC NRR.

The element carbon has been used as a source of energy for the past few hundred years, and now in this era of technology, carbon has played a significant and very prominent role in almost all fields of science and technology. So as an honour to this marvellous element, we humans should know about its various forms of existence. In this review article, we shed light on all possible carbon-allotropes; similarities in their synthesis techniques and the starting materials; their wide range of possible availability; and finally, future perspectives and applications. A brief introduction is given on the types, structures, and shapes of the allotropes of carbon for a better understanding.

Carbon nanomaterials have been extensively researched in the past few years owing to their interesting properties. The massive research efforts resulted in the emergence of carbon dots, which belong to the carbon nanomaterials family. Carbon dots (C-dots) have garnered the attention of researchers mainly due to their convenient availability from organic as well as inorganic materials and also due to the novel properties they exhibit. C-Dots have been said to overcome the era of quantum dots, referring to their levels of toxicity and biocompatibility. In this review, we focus on the discovery of C-dots, their structure and composition, surface passivation to enhance their optical properties, the various synthetic methods used, their applications in different areas, and future perspectives. Emphasis has been given to greener approaches for the synthesis of C-dots in order to make them cost effective as well as to improve their biocompatibility.

Designing new materials for sustainable energy and environmental applications is one of the prime focuses in chemical science.

Design and development of efficient photocatalysts for H2 production from water and sunlight have gained significant attention as the solar assisted approach is considered to be a promising approach for the generation of clean fuel. However, the poor charge carrier separation and light harvesting ability of existing photocatalysts limits the efficiency of photoconversion of water. In this work, the synthesis of transition metal ions (M2+ = Co2+, Cu2+, and Ni2+) coordinated with Ti‐metal organic frameworks (Ti‐MOFs) through a simple post‐synthetic coordination method for efficient solar light‐driven H2 production is reported. Notably, coordination of M2+ ions with Ti‐MOF significantly improves the optical absorption by d–d transitions and the multimetal sites facilitate the fast charge carrier separation, thereby enhancing the solar light‐driven H2 production activity. Very interestingly, the rate of solar light‐driven H2 production is varied with respect to different metal ions coordination due to the position of d–d bands absorption in the solar spectrum, and the complexing tendency of M2+ ions with sacrificial electron donors. A maximum solar H2 production rate of 1583.55 µmol h−1 g−1 is achieved with a Cu2+ coordinated Ti‐MOF, which is ≈13 fold higher than that of the pristine Ti‐MOF.

Synthesis of Carbon dots (C-dots) from bio-degradable waste is a much researched subject now-a-days. The demand for green chemistry and cost-effectiveness lead us to synthesize C-dots from kitchen waste. Nanometer sized carbon particles with unique optical properties were observed during the study. A simplistic approach was used for the synthesis which converted the waste materials into value-added products. Several different analyses were carried out on the obtained product which showed pristine results in comparison with the previous results.