A review on photocatalytic systems capable of synchronously utilizing photogenerated electrons and holes

TiO2–NGQD composite photocatalysts with switchable photocurrent response

“…Z-Scheme heterojunctions retard this pathway to lower energy for both holes and electrons and allow for the highest reduction and oxidation potential of the two materials to be utilized, which significantly increases their photocatalytic effectiveness. 22,23…”

“…Z-Scheme heterojunctions retard this pathway to lower energy for both holes and electrons and allow for the highest reduction and oxidation potential of the two materials to be utilized, which significantly increases their photocatalytic effectiveness. 22,23 Graphene quantum dots (GQDs) have received recent attention due to applications as bioimaging labels, 24 catalysts, 25 and sensitizers in dye sensitized solar cells. 26 Recently, several studies have proposed the use of GQDs/TiO 2 composite materials, which show enhanced photocatalytic efficiencies over their pure TiO 2 counterparts under UV illumination.…”

Highly Selective Photocatalytic Methane Oxidation to Methanol Using CO2 as a Soft Oxidant

“…Distinct from thermocatalysis, direct upgrading of CH 4 through photocatalysis provides a promising strategy that can break the thermal dynamics limitation with high activity under mild conditions. , During the photocatalysis process, photogenerated electrons (e – ) and holes (h + ) are generated by light excitation, and C–H bonds of CH 4 will be activated by h + as well as active species such as hydroxyl radicals ( • OH) . In addition, the rapid utilization of photogenerated electrons will inhibit the recombination of carriers and further promote the oxidation of methane by holes. , Generally, the photogenerated electrons are consumed by H + , O 2 , or extra sacrificial agents under the methane oxidation process. , In an aqueous environment, H + can consume e – to produce hydrogen, but the efficiency is extremely low . Meanwhile, the introduction of O 2 may lead to the formation of undesired byproducts due to its strong oxidizing ability. , Although some sacrificial agents, such as AgNO 3 , KBrO 3 , and 2,3-dichloro-5,6-dicyano- p -benzoquinone (DDQ), can be added as electron acceptors, they are not environmentally friendly with high cost. − Recently, carbon dioxide (CO 2 ) was introduced into the photocatalytic system as a soft oxidant, , which can promote the reaction performance by consuming the photogenerated electrons.…”

“…19 In addition, the rapid utilization of photogenerated electrons will inhibit the recombination of carriers and further promote the oxidation of methane by holes. 20,21 Generally, the photogenerated electrons are consumed by H + , O 2 , or extra sacrificial agents under the methane oxidation process. 22,23 In an aqueous environment, H + can consume e − to produce hydrogen, but the efficiency is extremely low.…”

Ag as an Electron Mediator in Porous Cu2O Nanostructures for Photocatalytic CO2 Reduction to CO

“…In order to realize a sustainable society, it is very important to develop new technologies that utilize renewable energy such as solar energy. − At present, it is an effective solution by using solar energy to capture and convert CO 2 for artificial photosynthesis. This breakthrough may provide innovative solutions to the energy, environmental, and economic challenges in the world. − Photocatalytic CO 2 reduction is a meaningful strategy that converts CO 2 into high-value hydrocarbon products by using solar energy. Solar energy can efficiently convert CO 2 into various chemical resources such as methane, ethylene, carbon monoxide, and so forth.…”