Photocatalytic Reforming of Biomass: What Role Will the Technology Play in Future Energy Systems

Algae: the game-changers in biohydrogen sector

Biohydrogen (H2) is an efficient form of renewable energy generated from various biological organisms. Specifically, primitive plants such as algae which are photosynthetic organisms can produce several commercial products, including biofuels due to their simple form, short life span, efficient photosynthetic capacity, and ability to grow in non-potable water sources. But these algae are often neglected and considered waste. Several studies have revealed the importance and role of algal species in generating biofuels, especially biohydrogen. Considerable research has been conducted in order to understand hydrogen production from algal sources. This review emphasizes the photolysis of water-based hydrogen production in algae apart from the metabolites fermentation process. The influence of physico-chemical factors, including oxygen scavengers, nanoparticles, and hydrogenases, was highlighted in this review to enhance H2 production from algal species. Also, several algal species used for hydrogen production are summarized in detail. Overall, this review intends to summarize the developments in hydrogen production from algal species keeping in view of excellent prospects. This knowledge certainly would provide a good opportunity for the industrial production of hydrogen using algal species, which is one of the most concerned areas in the energy sector.

Alternatives to water oxidation in the photocatalytic water splitting reaction for solar hydrogen production

The photocatalytic water splitting process to produce H₂ is an attractive approach to meet energy demands while achieving carbon emission reduction targets. However, none of the current photocatalytic devices meets the criteria for practical sustainable H₂ production due to their insufficient efficiency and the resulting high H₂ cost. Economic viability may be achieved by simultaneously producing more valuable products than O₂ or integrating with reforming processes of real waste streams, such as plastic and food waste. Research over the past decade has begun to investigate the possibility of replacing water oxidation with more kinetically and thermodynamically facile oxidation reactions. We summarize how various alternative photo-oxidation reactions can be combined with proton reduction in photocatalysis to achieve chemical valorization with concurrent H₂ production. By examining the current advantages and challenges of these oxidation reactions, we intend to demonstrate that these technologies would contribute to providing H₂ energy, while also producing high-value chemicals for a sustainable chemical industry and eliminating waste.