Fig. 1. (a) Jablonski schematic for [Ru(bpy)3]2+. (b) Schematic depicting an S0→T1 excitation. Reprinted with permission from Ref. [53] Copyright 2020 American Chemical Society.

Fig. 2. Photocatalytic performance of metal-defected TiO2. (a) Photocatalytic H2 evolution and quantum efficiency (QE). (b) The degradation rates of four organic pollutants (Phenol, MO, RhB, Rose Bengal). (c) Magnetization (M-H) curves measured at 300 K of TiO2-m. (d) Schematic illustration of suppression of recombination between electrons and holes due to spin-flip. (e) Time-resolved transient photoluminescence decay. From Ref. [43] CC BY 4.0.

Fig. 3. Different spin states of Co ions (a) and (b), amounts of HCOOH, CO, and CH4 produced over (c) COF-367-CoII and (d) COF-367-CoIII as a function of visible-light irradiation time. Reprinted with permission from Ref. [42] Copyright 2020 American Chemical Society.

Fig. 4. Calculated potential energy profile of CO2 reduction reaction to HCOOH catalyzed by (a) COF-367-CoII and (b) COF-367-CoIII. The Co(II), Co(III), C, N, O, and H atoms are demonstrated in green, red, gray, blue, orange, and light gray, respectively. Reprinted with permission from Ref. [42] Copyright 2020 American Chemical Society.

Fig. 5. Different coupling modes of CO2 and HCOOH interacting with Co site at different spin states for (a) CO2-adsorbed COF-367-CoII, (b) CO2-adsorbed COF-367-CoIII, (c) HCOOH-interacted COF-367-CoII, and (d) HCOOH-interacted COF-367-CoIII. The numerical values represent the corresponding OPDOS intensities. Reprinted with permission from Ref. [42] Copyright 2020 American Chemical Society.

Fig. 6. Control of hydrogen peroxide production. UV-vis absorption spectra from the titration of the used electrolyte (Na2SO4) with o-tolidine of bare TiO2 and TiO2 electrodes coated with (a) self-assembled Zn-porphyrins of either achiral (A-Zn) or chiral (S-Zn) and (b) TPyA molecules. The control refers to the titration of unused Na2SO4 with o-tolidine. (c) When the electrons transfer to the anodes is non-spin specific, the spins of the unpaired electrons on the two OH• are aligned antiparallel, hence, the interaction between the two OH• is on a single surface that correlates with the production of hydrogen peroxide (H2O2). (d) When the electron transfer to the anode is spin specific, the spins of the two electrons are aligned parallel to each other, hence, the two OH• interacts on a triplet surface that forbids the formation of H2O2 and facilitates the production of oxygen in its ground state. Reprinted with permission from Ref. [58] Copyright 2017 American Chemical Society.

Fig. 7. (a) Calculated eg occupancy of Mn-C3N4. (b) Partial density of states of Mn obtained by DFT calculation. (c) Correlation of eg occupancy and TOF values calculated by normalizing OER activity by per mole of Mn for Mn-C3N4. (d) A proposed four-electron mechanism for OER over Mn sites. (e) Photocatalytic pure water splitting performance of Mn-C3N4 under simulated sunlight (AM1.5, 100 mW cm-2). Reprinted with permission from Ref. [41] Copyright 2019 Wiley-VCH.

Fig. 8. (a) Photocatalytic degradation of MO with no magnetic field (NMF) or with a magnetic field (MF) in the presence of TiO2 nanobelts under 20 mW cm-2 UV illumination. The inset is a schematic diagram of the magnetic field photocatalytic setup. (b) Photocatalytic degradation of MO with magnetic fields of different magnetic induction intensities. (c) Schematic illustration of the proposed influence of the magnetic field on photoinduced charge carrier separation in the TiO2 nanobelts. From Ref. [37] CC BY 4.0.

Fig. 9. (a) Schematic diagram of the experimental setup showing the magnetic field-assisted photocatalytic H2 production system. (b) Photocatalytic H2 production for different magnetic induction intensities in the presence of Au NR-CdS NP under 160 mW cm-2 300 W Xe lamp illumination. (c) Schematic diagram of the enhancement of photocatalysis with the metal-semiconductor core-shell structure in a magnetic field. Reprinted with permission from Ref. [46] Copyright 2020 Elsevier.

Fig. 10. Schematic illustration of the magnetic field provided a driving force to promote NO3- and NH4+ adsorption. Reprinted with permission from Ref. [32] Copyright 2018 Elsevier.

Fig. 11. (a) Photocatalytic degradation of RhB with various magnetic fields in the presence of α-Fe2O3/RGO hybrid nanostructures under Xe light irradiation. (b) Kinetic curves of the degradation of RhB by α-Fe2O3/RGO composites under different magnetic fields. (c) Photocatalytic degradation of several different pollutants between NMF and 6 kOe fields in the presence of α-Fe2O3/RGO hybrid nanostructures under Xe light irradiation of 40 min. The inner error bars correspond to the standard errors of the mean within each measurement. (d) Magnetotransport properties of α-Fe2O3 and α-Fe2O3/RGO composites at room temperature. Reprinted with permission from Ref. [64] Copyright 2018 American Chemical Society.