Metal Oxide-Based Photocatalytic Paper: A Green Alternative for Environmental Remediation

Abstract

The interest in advanced photocatalytic technologies with metal oxide-based nanomaterials has been growing exponentially over the years due to their green and sustainable characteristics. Photocatalysis has been employed in several applications ranging from the degradation of pollutants to water splitting, CO2 and N2 reductions, and microorganism inactivation. However, to maintain its eco-friendly aspect, new solutions must be identified to ensure sustainability. One alternative is creating an enhanced photocatalytic paper by introducing cellulose-based materials to the process. Paper can participate as a substrate for the metal oxides, but it can also form composites or membranes, and it adds a valuable contribution as it is environmentally friendly, low-cost, flexible, recyclable, lightweight, and earth abundant. In term of photocatalysts, the use of metal oxides is widely spread, mostly since these materials display enhanced photocatalytic activities, allied to their chemical stability, non-toxicity, and earth abundance, despite being inexpensive and compatible with low-cost wet-chemical synthesis routes. This manuscript extensively reviews the recent developments of using photocatalytic papers with nanostructured metal oxides for environmental remediation. It focuses on titanium dioxide (TiO2) and zinc oxide (ZnO) in the form of nanostructures or thin films. It discusses the main characteristics of metal oxides and correlates them to their photocatalytic activity. The role of cellulose-based materials on the systems’ photocatalytic performance is extensively discussed, and the future perspective for photocatalytic papers is highlighted.

Synthesis of Heterostructure of ZnO@MOF-46(Zn) to Improve the Photocatalytic Performance in Methylene Blue Degradation

“…(αhν) 2 = K (hν − Eg) (1) where hν is the photon energy (eV), K is a constant related to the material, α is the absorption coefficient, and Eg is the band gap energy (eV). The band gaps of cubic ZnO(1), cuboctahedral ZnO(2), and octahedral ZnO(3) are 3.28, 3.15, and 3.11 eV, respectively.…”

“…Photocatalytic processes with metal-oxide-based photocatalysts have been employed in several applications, especially the degradation of various pollutants [1][2][3]. Zinc oxide (ZnO) has been widely used in numerous potential applications, including biosensors [4], light-emitting diodes (LEDs) [5], solar cells [6], gas sensors [7], and photocatalysis [8] due to its attractive properties, such as nontoxicity, chemical/thermal stability, low cost, and high mobility of electrons in the conduction band.…”

Enhanced Fe-TiO2 Solar Photocatalysts on Porous Platforms for Water Purification

“…Concerning photocatalysts, TiO 2 is in the spotlight and the subject of intense research, due to its remarkable properties, which include a strong oxidation potential to decompose organic pollutants, physical and chemical stabilities, low cost, non-toxicity, and earth abundance [ 10 , 11 , 12 , 13 , 14 , 15 ]. TiO 2 is widely used in photocatalysis for the degradation of contaminants, in both aqueous and gaseous mediums [ 16 ].…”

Silver-doped SnO2nanostructures for photocatalytic water splitting and catalytic nitrophenol reduction

“…16,17 Metal oxide semiconductors possess a low price, environmental friendliness, recyclability, abundant accessibility, and excellent degradation proficiency. 18–22…”