Recently, carbon dioxide capture and conversion, along with hydrogen from renewable resources, provide an alternative approach to synthesis of useful fuels and chemicals. People are increasingly interested in developing innovative carbon dioxide hydrogenation catalysts, and the pace of progress in this area is accelerating. Accordingly, this perspective presents current state of the art and outlook in synthesis of light olefins, dimethyl ether, liquid fuels, and alcohols through two leading hydrogenation mechanisms: methanol reaction and Fischer-Tropsch based carbon dioxide hydrogenation. The future research directions for developing new heterogeneous catalysts with transformational technologies, including 3D printing and artificial intelligence, are provided.

Visible light-responsive photocatalytic technology holds great potential in water treatment to enhance purification efficiency, as well as to augment water supply through the safe usage of unconventional water sources. This review summarizes the recent progress in the design and fabrication of visible light-responsive photocatalysts via various synthetic strategies, including the modification of traditional photocatalysts by doping, dye sensitization, or by forming a heterostructure, coupled with π-conjugated architecture, as well as the great efforts made within the exploration of novel visible light-responsive photocatalysts. Background information on the fundamentals of heterogeneous photocatalysis, the pathways of visible light-responsive photocatalysis, and the unique features of visible light-responsive photocatalysts are presented. The photocatalytic properties of the resulting visible light-responsive photocatalysts are also covered in relation to the water treatment, i.e., regarding the photocatalytic degradation of organic compounds and inorganic pollutants, as well as photocatalytic disinfection. Finally, this review concludes with a summary and perspectives on the current challenges faced and new directions in this emerging area of research.

This review provides a comprehensive assessment of recently improved carbon dioxide (CO₂) separation and capture systems, used in power plants and other industrial processes. Different approaches for CO₂ capture are pre-combustion, post-combustion capture, and oxy-combustion systems, which are reviewed, along with their advantages and disadvantages. New technologies and prospective “breakthrough technologies”, for instance: novel solvents, sorbents, and membranes for gas separation are examined. Other technologies including chemical looping technology (reaction between metal oxides and fuels, creating metal particles, carbon dioxide, and water vapor) and cryogenic separation processes (based on different phase change temperatures for various gases to separate them) are reviewed as well. Furthermore, the major CO₂ separation technologies, such as absorption (using a liquid solvent to absorb the CO₂), adsorption (using solid materials with surface affinity to CO₂ molecules), and membranes (using a thin film to selectively permeate gases) are extensively discussed, though issues and technologies related to CO₂ transport and storage are not considered in this paper.