Photocatalytic transition-metal-oxides-based p–n heterojunction materials: synthesis, sustainable energy and environmental applications, and perspectives

Current perspective in metal oxide based photocatalysts for virus disinfection: A review

“…3 b) ( Nasir et al, 2021 ; Lu et al, 2019a , 2022 ; Li et al, 2021 ; He et al, 2019 ). The photocatalytic reaction takes place under the combined action of solar light with suitable frequency and the photoactive material that absorbs a wide range of solar spectra ( Soni et al, 2022a , 2022b ). Typically, by acquiring an excited state after the absorption, single e − migration event triggers to produce active e − /h + pairs in the conduction band (CB) and valence band (VB) of photoactive semiconductor, respectively ( Soni et al, 2021a ; Lu et al, 2019b , 2020 ).…”

“…Typically, by acquiring an excited state after the absorption, single e − migration event triggers to produce active e − /h + pairs in the conduction band (CB) and valence band (VB) of photoactive semiconductor, respectively ( Soni et al, 2021a ; Lu et al, 2019b , 2020 ). Isolated e − in the CB can reduce dissolved O 2 and produce H 2 O 2 , or •O 2 − along with H + ions, whereas, remaining h + in the VB can oxidize the OH − ions from water to generate unstable •OH radicals ( Soni et al, 2021b , 2022a ; Wang et al, 2021 ). These generated reactive oxygen species (ROS; •OH, H 2 O 2 , H + , and •O 2 − ) during photocatalysis having redox potential participates in photocatalytic disinfection and degradation processes ( Soni et al, 2021c ; Kumar et al, 2021a ).…”

In Vitro Diagnostic Examination and Prognosis Surveillance by Hierarchical Heterojunction-Assisted Metabolic Analysis

“…The metal oxide p−n junction consisting of p-and n-type semiconductors has been regarded as an effective structure for charge trapping and separation, since the heterojunction can form a built-in electric field at the two-phase interface to hinder the recombination of electron−hole pairs. 20,21 Generally, the built-in electric field will lead p-zone electrons to go through the p−n junction into the n-zone and n-zone holes to go into the p-zone when excited by the appropriate light source. 21,22 Furthermore, the high thermal capacity, high photothermal conversion, and low thermal conductivity of matrix materials favor photoionization and thermally driven desorption during LDI-MS, 23 which can reduce thermal dissipation from materials themselves to the target plate and facilitate high-efficiency desorption of the analytes.…”

“…20,21 Generally, the built-in electric field will lead p-zone electrons to go through the p−n junction into the n-zone and n-zone holes to go into the p-zone when excited by the appropriate light source. 21,22 Furthermore, the high thermal capacity, high photothermal conversion, and low thermal conductivity of matrix materials favor photoionization and thermally driven desorption during LDI-MS, 23 which can reduce thermal dissipation from materials themselves to the target plate and facilitate high-efficiency desorption of the analytes. In this respect, metal oxides are relatively superior, hence receiving extensive attention in the detection of various low-molecular compounds.…”

“…Moreover, noble metals are capable of improving LDI efficiency because of their surface plasma resonance effect that can generate large densities of hot electrons under excitation conditions, which is beneficial to improve the adsorption and desorption of metabolites. , Drawing inspiration from the above-mentioned studies, it is very much possible that the transfer and separation efficiency of electron–hole pairs can be improved by adjusting the number and type of interfaces. The metal oxide p–n junction consisting of p - and n -type semiconductors has been regarded as an effective structure for charge trapping and separation, since the heterojunction can form a built-in electric field at the two-phase interface to hinder the recombination of electron–hole pairs. , Generally, the built-in electric field will lead p-zone electrons to go through the p–n junction into the n-zone and n-zone holes to go into the p-zone when excited by the appropriate light source. , Furthermore, the high thermal capacity, high photothermal conversion, and low thermal conductivity of matrix materials favor photoionization and thermally driven desorption during LDI-MS, which can reduce thermal dissipation from materials themselves to the target plate and facilitate high-efficiency desorption of the analytes. In this respect, metal oxides are relatively superior, hence receiving extensive attention in the detection of various low-molecular compounds. , As a result, the metal oxide heterojunction is worthy of being anticipated …”