Photocatalytic production of hydrogen from biomass-derived feedstocks

Abstract

The application of photocatalysis for the utilisation of sunlight energy is intensely investigated in present times, particularly in prospect of generating solar fuels by hydrogen production or CO2 reduction processes as tools for societies aiming to relief their thirst for fossil resources. From the perspective of sustainability, the rational use of biomass-derived feedstocks for photocatalytic H2 production is a feasible, proven and highly efficient process. In this review, in addition to delving into physico-chemical fundamentals of photocatalytic processes on semiconductors, the research activity on this topic related to design of revolutionary semiconductor-based materials, generally including metallic nanoparticles or complexes as hydrogen-evolving co-catalysts, is outlined and critically evaluated. Moreover, the use of sunlight and renewable feedstocks for the generation of hydrogen, as a compelling opportunity for the energy sector, is emphasised. Special focus is also set on the valorisation of biorefinery products, agricultural residues and industrial or municipal waste.

Hydrogen Generation through Solar Photocatalytic Processes: A Review of the Configuration and the Properties of Effective Metal-Based Semiconductor Nanomaterials

“…Heterojunction-based nanosized photocatalysts have been widely investigated in the literature review for photoreforming of several organic compounds [14,22,29,48]. Different preparation methods were adopted by researchers, such as the sol-gel method, photodeposition, photoelectrochemical deposition, wet impregnation, thermal, solvothermal and hydrothermal methods, precipitation, chemical vapor deposition, etc.…”

“…An extensive classification of organic compounds that could be used as sacrificial agents has been recently drawn up [14].…”

“…Straddling water photosplitting and organic photo-oxidation [99], photocatalytic reforming usually employs short chain alcohols (i.e., methanol, ethanol and glycerol), carboxylic acids (i.e., formic acid and oxalic acid) and carbohydrates (i.e., glucose) or biomass-derived substrates [14,100,101] as sacrificial organic species. As biomass-derived species may be often found in paper and food industry effluents [102,103], photoreforming may be regarded as an outstanding approach combining wastewater treatment and the generation of a high added value energy carrier.…”

“…Especially, thermochemical [6], photoelectrochemical [7][8][9][10] and photochemical processes [11,12] can be employed for solar hydrogen generation. Photocatalytic hydrogen generation can be achieved through water photosplitting [13] or photoreforming of organic species [14]. Solar photocatalytic processes for H 2 production need catalysts able to absorb radiation in the visible range and efficiently use it to promote electrons to the energy level required for hydrogen formation [15].…”

Biomolecule-assisted synthesis of defect-mediated Cd1−xZnxS/MoS2/graphene hollow spheres for highly efficient hydrogen evolution

“…Over the last few decades, numerous semiconductor photocatalysts for H 2 production have been investigated, such as TiO 2 , ZnO, CdS and C 3 N 4 . [1][2][3][4][5][6][7][8][9][10] However, the low photocatalytic efficiency and the utilization of noble metals (such as Pt, Ru and Rh) as cocatalysts are still the key factors that restrict the large-scale industrial application of this technology. 11 Therefore, new material strategies are highly desirable to develop more efficient photocatalytic systems based on inexpensive and earth abundant elements.…”