High Visible Light Photocatalytic Activity Research Articles

Heterostructured S-TiO2/g-C3N4 Photocatalysts with High Visible Light Photocatalytic Activity

Novel heterojunctions associating graphitic carbon nitride g-C3N4 and S-doped TiO2 nanoparticles were successfully designed and prepared via a hydrothermal method and used for photocatalytic degradations. The loading in S-TiO2 nanoparticles on g-C3N4 was varied (5, 10 and 20 wt%), and the photocatalysts were characterized by XRD, FT-IR, solid-state UV-visible diffuse reflectance, photoluminescence, XPS, TEM and SEM. The S-TiO2 (5%)/g-C3N4 catalyst exhibits the highest activity for the photocatalytic degradation of the methylene blue (MB) dye under visible light irradiation. The high photocatalytic performance originates from the enhanced separation and transfer of photogenerated charge carriers. The S-TiO2 (5%)/g-C3N4 photocatalyst is stable and can be reused five times without a sharp drop in activity, indicating its high potential for wastewater remediation.

Novel Bi2O2Se/BiOCl with high visible light photocatalytic activity for environmental remediation: Effective layer to layer interfacial charge transfer based on heterojunction

The photocatalytic activity of promising layered structure BiOX (X = Cl, Br, I) is limited by the low carrier mobility and charge transfer based on heterojunction. Hereon, we reported that Bi2O2Se with the same layered structure, high carrier mobility and broad spectrum absorption was used to composited with BiOCl to obtain effective layer to layer interfacial charge transfer and high photocatalytic activity under visible light. Bi2O2Se/BiOCl were synthesized via ion exchange method in precursor of Bi2O2Se. 25-Bi2O2Se/BiOCl shows the optimal photocatalytic removal activity of methyl blue (MB) and Cr (VI), which was higher than that of pure BiOCl and Bi2O2Se. The analysis of morphology revealed the in-growth mechanism of Bi2O2Se/BiOCl. A strong interaction between the same layer structure Bi2O2Se and BiOCl was proved by detailed analysis of XPS and valence charge density. Transient photocurrent responses and energy-level indicated the sensitized electrons of Bi2O2Se can be injected into BiOCl effectively and produce H2O2. We believe layer structure Bi2O2Se can be candidate co-catalyst to expand photocatalytic activity of layer structure semiconductor catalysts in the visible and infrared regions, especially, for the same layered bismuth compounds.

One-dimensional Bi2MoO6 nanosheets/TiO2 hollow tubes:Controllable synthesis and enhanced visible photocatalytic activity

By electrostatic spinning technology combined with solvothermal method, Bi2MoO6 nanosheets were loaded on TiO2 hollow tubes, and Bi2MoO6/TiO2 nanocomposite photocatalytic materials were successfully prepared. The products were characterized by scanning electron microscopy (SEM), Transmission electron microscopy (TEM),X-ray diffraction (XRD), ultraviolet–visible spectroscopy (UV–vis) and photoluminescence spectroscopy (PL). The results show that the lamellar Bi2MoO6 nanostructures were successfully grown on TiO2 hollow tubes. The photocatalytic experiments showed that the Bi2MoO6/TiO2 nanocomposites exhibited higher visible light photocatalytic activity than both pure TiO2 and pure Bi2MoO6, which may be due to the effective photogenerated electron-hole separation generated by the Bi2MoO6/TiO2 heterojunction, the photocatalytic degradation of detetracycline, doxycycline and aureomycin by Bi2MoO6/TiO2 photocatalytic system was also compared. In addition, the Bi2MoO6/TiO2 photocatalyst maintained good photocatalytic performance after five cycles, and it was demonstrated by the capture experiments that the superoxide radical played a dominant role in the photocatalytic degradation process, and the contributions of light-generated holes and hydroxyl radicals were approximately the same, and the possible mechanism of its photocatalytic system was proposed.

Solid-state synthesis of ZnS/ZnO nanocomposites and their decoration with NiS cocatalyst for photocatalytic hydrogen production

Herein was demonstrated the facile solid-state synthesis of ZnS/ZnO nanocomposites using planetary ball milling followed by subsequent thermal treatment. X-ray diffraction analysis has shown that the ZnS/ZnO products are nanocrystalline with an estimated crystallite size of less than 60 nm. A transmission electron microscope has demonstrated the presence of spherical heterostructures and core-shell structured ZnS/ZnO nanocomposites with the size being 40–80 nm in diameter. Fourier transform infrared spectroscopy analysis confirmed the presence of Zn–O and Zn–S bonds. The formation of a thin boundary between the ZnS and ZnO phases, where the sulfur oxidation state varies from −2 to +6, was determined by X-ray photoelectron spectroscopy. Degradation of methylene blue and Orange II organic dyes was used to assess the photocatalytic activity of ZnS/ZnO nanocomposites, and the nanocomposites of ZnS/ZnO, with a mass ratio of ∼1:1, demonstrated the highest visible light photocatalytic activity. For photocatalytic hydrogen production experiments, the surface of ZnS/ZnO nanocomposites was in situ decorated with NiS nanoparticles, where the mass content of NiS was 1.5%. The presence of NiS cocatalyst promotes the separation and transfer of photogenerated charges, thereby increasing the photocatalytic activity of ZnS/ZnO nanocomposites during hydrogen generation. The apparent quantum efficiency of photocatalytic hydrogen generation using ZnS/ZnO-3h-NiS photocatalyst was equal to 1.13%. This contribution shows the possibility to prepare nano-structured photocatalysts via mechanochemistry.

Controllable Al2O3 coating makes TiO2 photocatalysts active under visible light by pulsed chemical vapor deposition

TiO2 catalysts, modified by coating Al2O3, presented high visible-light photocatalytic activity. Al2O3 nano-films were successfully deposited onto TiO2 particles using AlCl3 as a precursor via the pulsed chemical vapor deposition process. And, the alumina was anchored onto TiO2 surface via Ti–O–Al bonds. The morphology, constitution, photocatalytic activity and photoelectrochemical performance of the Al2O3-coated TiO2 were characterized. Controllable Al2O3 coating increased the oxygen vacancies and hydroxyl groups, and induced the formation of surface disordered TiO2 layer, which enhanced light absorption, increased charge carrier separation and transfer efficiency, and surface redox efficiency. Therefore, the TiO2/Al2O3 catalyst obtained via the pulsed chemical vapor deposition technique may break through the limitation of the band gap, and the pulsed chemical vapor deposition provided an effective strategy for the TiO2 production with active defective sites.

MIL-53(Fe)@BiOBr/TCN/Ti photoanode assembled visible light responsive photocatalytic fuel cell to enhance rhodamine B degradation and electricity generation

In this research, MIL-53(Fe)@BiOBr/TCN/Ti photoanode was created using the secondary silica sol drop coating method, and assembled with Cu cathode to form photocatalytic fuel cell (PFC) to degrade rhodamine B and generate electricity. The resulting PFC has high visible light response and photocatalytic activity. It has a rhodamine B degradation efficiency of 92.19%, a maximum power density of 6.2 μW cm−2, and a maximum photocurrent density of 0.11 mA cm−2. Its strong photocatalysis capabilities benefits from the wider light absorption range and lower charge carrier recombination rate of the photoanode. The double Z-scheme heterojunction formed among BiOBr, MIL-53(Fe) and TCN in the composite catalyst of the photoanode provide more transfer channels for photogenerated e− and encourage the separation of e−-h+ pairs. ∙OH and ∙O-2 are the main active substances for rhodamine B degradation. This study offers a novel approach to the development of high-efficiency photoanodes for PFC.

Facile fabrication of graphitic carbon nitride by solvothermal method with hierarchical structure and high visible light photocatalytic activity

BackgroundAt present, graphitic carbon nitride(g-C3N4) has been tremendously investigated as a visible light photocatalyst due to its excellent physical and chemical stability, easy fabrication, diverse morphology and tunable band structure. However, small surface area and high recombination of photogenerated electron-hole pairs hinder the photocatalytic activity of the pristine g-C3N4. Up to now, most of the g-C3N4 is prepared by the time-consuming, cumbersome and energy-consuming methods such as template and high temperature calcination. MethodsA novel graphitic carbon nitride with hierarchical structure and high photocatalytic activity was first time synthesized by the solvothermal method without high-temperature calcination using two monomers (cyanuric chloride and melamine) as the reactants. Morphologies and structure of graphitic carbon nitride were characterized by FTIR, XRD, XPS, FESEM, BET, etc. Effects of monomer molar ratio on the microstructure, band structure and electron transfer process of the samples were systematically investigated. The radical trapping experiments and Mott-Schottky analysis were carried out to reveal the photocatalytic degradation mechanism. Significant findingsDue to the high activity of Cl group of cyanuric chloride, HCl generated by condensation dramatically influences the formation of the porous structure. With the increase of cyanuric chloride molar ratio, polymerization reaction between cyanuric chloride and melamine became more complete, structure of graphite carbon nitride gradually changed from 1D nanorods to 2D layered structures, and the band structure and electron transfer properties were effectively improved. Due to the synergistic effect of specific surface area and electron transfer performance, 2-CN-1 with microporous 1D and 2D structures showed excellent photocatalytic performance (96.5% after 30 min illumination) and stability (photocatalytic performance only decreased by 4.5% after five cycles) in the condition of methyl orange (MO) concentration as high as 20 mg/L and photocatalyst amount as low as 20 mg. In this study, the effective control of graphitic carbon nitride morphology by way of new condensation mode via solvothermal method without both template and high temperature calcination provides a new strategy for the graphitic carbon nitride with high visible light photocatalytic activity.

Hydrolysis‐Induced InOx on ZnIn2S4 Promotes Selective CO2 Photoreduction over H2 Evolution

AbstractMetal sulfides generally show high visible light photocatalytic activity, but lower selectivity in the CO2 photoreduction due to the competitive hydrogen evolution. Here, a partial hydrolysis method is reported to promote the selective photocatalytic CO2 reduction over ZnIn2S4. The ZnIn2S4 was post‐hydrolyzed in an aqueous ammonia solution to form oxide species (ZIS‐[InOx]). Detailed experiment and DFT calculation demonstrated that the post‐hydrolysis treatment facilely prohibits the recombination of photogenerated charge carriers and benefits CO2 activation. Under visible light irradiation, the ZIS‐[InOx] photocatalyst shows enhanced CO2‐to‐CO conversion activity with a CO‐evolving rate of 1771 μmol g−1 h−1, which is about 8 times higher than that over pristine ZIS and 3.5 times higher than that over bulk ZIS/In2O3. More importantly, the post hydrolysis treatment significantly prohibits the hydrogen evolution and increases the CO/H2 ratio from 0.08 over ZIS to 1.8 over ZIS‐[InOx]. This work provides a new strategy to prepare catalysts for photocatalytic CO2 reduction.

Removal of tetracycline from wastewater using g-C3N4 based photocatalysts: A review

Tetracycline is currently one of the most consumed antibiotics for human therapy, veterinary purpose, and agricultural activities. Tetracycline worldwide consumption is expected to rise by about more than 30% by 2030. The persistence of tetracycline has necessitated implementing and adopting strategies to protect aquatic systems and the environment from noxious pollutants. Here, graphitic carbon nitride-based photocatalytic technology is considered because of higher visible light photocatalytic activity, low cost, and non-toxicity. Thus, this review highlights the recent progress in the photocatalytic degradation of tetracycline using g–C3N4–based photocatalysts. Additionally, properties, worldwide consumption, occurrence, and environmental impacts of tetracycline are comprehensively addressed. Studies proved the occurrence of tetracycline in all water matrices across the world with a maximum concentration of 54 μg/L. Among different g–C3N4–based materials, heterojunctions exhibited the maximum photocatalytic degradation of 100% with the reusability of 5 cycles. The photocatalytic membranes are found to be feasible due to easiness in recovery and better reusability. Limitations of g–C3N4–based wastewater treatment technology and efficient solutions are also emphasized in detail.

Nano particle/microsphere TiO2/BiOBr Z-scheme heterojunction with high visible-light photocatalytic activity in tetracycline hydrochloride degradation

Nano particle/microsphere TiO2/BiOBr Z-scheme heterojunction with high visible-light photocatalytic activity in tetracycline hydrochloride degradation

Flexible PAN-Bi2O2CO3–BiOI heterojunction nanofiber and the photocatalytic degradation property

In this paper, one-dimensional PAN-Bi2O2CO3–BiOI photocatalytic nanofibers were prepared using flexible PAN nanofibers as carriers. Bi2O2CO3 was first grown on the surface of PAN nanofibers, and then BiOI was loaded on Bi2O2CO3 by ion exchange method. The characterization results showed that PAN-Bi2O2CO3–BiOI nanofibers have a diameter of about 210 nm and regular fiber morphology. The results of UV–Vis diffuse reflectance spectroscopy, XRD and XPS showed that Bi2O2CO3–BiOI composed of granular semiconductor nano heterostructures with high specific surface area were uniformly loaded on the surface of PAN fiber. The photocatalytic degradation experiment of the material showed high visible light photocatalytic activity. The preparation of Bi2O2CO3–BiOI heterojunction improved the photoelectron hole separation efficiency of BiOI under visible light. PAN-Bi2O2CO3–BiOI fibers showed high photocatalytic degradation efficiency for rhodamine B. The degradation efficiency was more than 95% within 120 min irradiation. Free radical trapping experiments showed photocatalysts mainly produced O2−,·OH and h+, which played a major role in photocatalysis.

Carbohydrate-regulated synthesis of ultrathin porous nitrogen-vacancy polymeric carbon nitride for highly efficient Visible-light hydrogen evolution

Morphologies and electronic structures of the photocatalysts play a critical role in governing their photocatalytic actives via providing large specific surface area (more active sites) and suitable band structure. To achieve high visible-light photocatalytic activity, herein, an ultrathin porous nitrogen-vacancy polymeric carbon nitride (PCN) was synthesized by high-temperature thermal polymerization using melamine with a biomass derived carbohydrate aqueous solution, offering a flexible nature to finely tune the vacant and porous structures through properly changing the carbohydrate. The ultrathin porous structure could significantly enhance the specific surface area of PCN and improve the mobility of charges. Moreover, the induced vacancies structures could largely expand the light absorption range and reduce the recombination rate of photogenerated carriers. These led to an excellent photocatalytic activity for H2 production, with the optimal hydrogen evolution rate 17.2 times (5.5 mmol h−1 g−1, 1 wt.% Pt as a co-catalyst) higher than that of the unmodified PCN (0.32 mmol h−1 g−1). These results provide a simple, effective, and cost-effective strategy for the synthesis of novel photocatalysts using biomass-based raw materials to obtain a highly active photocatalyst with simultaneous adjusting the vacancies and porous structures.

Review on the Synthesis Method of Nanocomposites and Approach to Making Semiconductors Visible Light Active

Many studies have been concentrated on the degradation of toxic organic compounds in waste water via photocatalysis of various semiconductors. It has attracted great attention in modern science because of its potential in solving many current environmental problems such as air and water pollution. The common photocatalysts are primarily nanocomposite metal oxides, are known to be good photocatalysts for the degradation of several environmental contaminants due to their high photosensitivity, stability and non-toxic nature. There are different approaches for the synthesis of nanomaterials: Top down and bottom up approaches. Top- down approach is best approach and refers to successive cutting of a bulk material to get nano sized particles. These applications have their interest in controlling particle size, particle shape, size distribution, particle composition and degree of particle agglomeration. Some nanoparticles have large band-gap which leads to high recombination rate of photogenerated electron–hole pairs limit their utilization for photocatalytic applications. More recently, significant efforts have also been made to develop new or modified semiconductor photocatalysts that are capable of using visible-light (λ = 400–700 nm) including semiconductor coupling, metal ion doping, nonmetallic element doping, and sensitization with organic dyes. Coupling of two semiconductor nanoparticles with different band gap widths has been demonstrated in many studies as one of the most effective ways to reduce the recombination of electron–hole pairs and consequently, achieving a higher photocatalytic activity. Moreover, the ternary nanocomposites have high visible light photocatalytic activity and organic dyes can be decomposed efficiently, implying the higher photocatalytic activity of the ternary nanocomposites.

Sol–Gel Synthesis and Photocatalytic Activity of Graphene Oxide/ZnFe2O4-Based Composite Photocatalysts

ZnO (ZO), Fe2O3 (FO), and graphene oxide (GO)/ZO/FO/ZnFe2O4 (ZFO) composite photocatalysts have been synthesized successfully via a simple sol–gel method and low-temperature technology. The phase structure and microstructural analysis confirmed that the GO/ZO/FO/ZFO magnetic separation photocatalyst is composed of GO, hexagonal ZnO, rhombohedral Fe2O3, and spinel ZnFe2O4 without any other impurities. The GO/ZO/FO/ZFO composite photocatalysts have a high visible light optical absorption coefficient and photocatalytic activity for degrading dyes, refractory pollutants, and antibiotics. The degradation percentages of methyl orange, tetrabromobisphenol A, and oxytetracycline hydrochloride by the GO/ZO/FO/ZFO magnetic separation photocatalyst were 98% for 180 min, 99% for 150 min, and 85% for 180 min, respectively. The special synthesis path leads to the formation of a special heterojunction between GO, ZnO, Fe2O3, and ZnFe2O4, which does not change the optical band gap value of the main lattice Fe2O3, and enhances the surface defects of the GO/ZO/FO/ZFO magnetic separation photocatalyst, resulting in high charge carrier transfer and separation efficiency of the catalyst and then enhanced the photocatalytic activity of the GO/ZO/FO/ZFO magnetic separation photocatalyst.

Superior efficiency of BN/Ce2O3/TiO2 nanofibers for photocatalytic hydrogen generation reactions

One-dimensional BN/Ce2O3/TiO2 heteroarchitectures with high visible-light photocatalytic activity have been successfully obtained by an electrospinning technique. The properties of the prepared nanofibers were controlled using different ratios of cerium. The results of XPS characterization revealed that the Ce element is present in the valence state + III on the surface of the TiO2 nanofibers. Rietveld refinement of XRD data reveals that introducing small concentrations of Ce3+ (<3.0 at%) into the electrospinning solution leads to the formation of small amounts of rutile and brookite phases, a decrease in the crystallite size of the main anatase phase and a slight decrease in the c parameter and unit cell volume of the anatase phase. In contrast, only the anatase phase, which has a similar crystallite size and lattice parameters to that formed in the undoped sample, is observed when 3 at.% Ce is used. These results suggest that Ce3+ ions did not substitute Ti4+ ions in the lattice of both anatase and rutile phases, which can be explained by the large difference in the ionic radius of Ti4+ and Ce3+ ((r (Ti4+) = 60.5 pm, r (Ce3+) = 101.7 pm). Scanning electron microscopy demonstrates that the diameter of the obtained nanofibers decreases from 240 nm for pristine TiO2 to 101 nm, 70 nm, 40 nm for 2% Ce/TiO2 (CET2), BN/TiO2 (BT) and BN/2% Ce/TiO2 (BCET2), respectively. The d-spacing decreased by 0.3 nm after Ce incorporation as demonstrated by high-resolution transmission electron microscopy. XPS proved the presence of BN nanosheets along with Ce2O3 and TiO2 into the nanofibers. Compared with the pure TiO2 nanofibers (NF), the obtained Ce/Ti ratio of 2% (molar ratio) showed an enhancement of the visible-light photocatalytic activity to water splitting, which is 46 times higher than that of bare TiO2 NF. The Ce2O3 might improve the separation of photogenerated electrons and holes derived from the coupling effect of TiO2 and cerium oxide. This work also examines the modification of TiO2 (anatase) properties with hexagonal boron nitride (h-BN) and the impact this coupling has on photocatalytic activity. XPS proved the presence of BN nanosheets along with Ce2O3 and TiO2 into the nanofibers. The electron transfer rate was improved by BN exfoliation. The photocatalytic results indicated that the BN/Ce2O3/TiO2 nanofibers improve hydrogen production up to 5100 μmol/g for 6 h under visible light, which could be due to the presence of BN sheets that enhanced the separation of the photo-induced electron–hole pairs in TiO2 and increased the specific surface area compared to pure TiO2 and Ce2O3/TiO2 nanofibers. Moreover, the BN/Ce2O3/TiO2 could be easily recycled without decrease in the photocatalytic activity because of its one-dimensional nanostructure nature. Moreover, the present work focuses on the ternary composite of BN/Ce2O3/TiO2 for optimization of electronic and phonon transport properties using the state-of-the-art density functional theory (DFT). The calculated electronic density of states (DOS) modulus shows an excellent agreement compared with available theoretical and experimental data for hydrogen production.

Engineering unsaturated coordination of conductive TiOx clusters derived from Metal–Organic–Framework incorporated into hollow semiconductor for highly selective CO2 photoreduction

Solar-driven CO2 conversion into fuels is a promising solution toward green energy conversion. It is a challenge to regulate the precise structure of photocatalysts at the atomic scale, facilitating the charge transfer and improving CO2 photoreduction performance. Herein, conductive Ti3+-rich TiOx clusters with unsaturated Ti–O5 coordination incorporated into nanosheets-assembled hollow sulfide semiconductors were prepared through a versatile transformation strategy by using NH2-MIL-125(Ti) metal–organic–framework as precursor. This typical photocatalysts exhibit highly selective photoreduction of CO2, achieving a super high visible-light photocatalytic CO evolution activity of 1100 μmol g−1h−1. The active sites were identified on the surface of conductive TiOx clusters, inducing efficient trapping of photogenerated electrons at the interface and suppressing H2 generation. This enhanced performance is ascribed to Ti3+-rich TiOx clusters as an efficient cocatalyst on sulfide semiconductor providing more active sites due to electrical conductivity and unsaturated coordination environment. This work provides a promising approach to enhance photocatalytic performance of the catalysts coupled by unique metal oxide clusters for selective photoreduction of CO2.

Fabrication and characterization of a TiBs@MCN cable-like photocatalyst with high photocatalytic performance under visible light irradiation

A cable-like photocatalyst, TiBs@MCN, with a larger specific surface area and higher visible-light photocatalytic activity, is successfully fabricated by an in situ hydrothermal self-assembly approach.

Sasol and UCT researchers collaborate on the use of commercial iron catalysts to convert hydrogen and CO2 into green jet fuel and chemicals

This study introduces a simple and fluorine free route to synthesize nitrogen and lanthanum co-doped TiO2 nanocrystals with exposed {0 0 1} facets through one-step hydrothermal method. The microstructure, chemical composition, and photocatalytic property of the co-doped TiO2 nanosheets were analyzed using XRD, FESEM, TEM, XPS and UV–vis. The experimental results indicated that N had been successfully doped into TiO2 lattice, while La was likely to form a binary nanocomposite with TiO2. The co-doped TiO2 nanosheets showed an additional visible light absorption band starting from 400 nm, which could improve the visible light photocatalytic activity of the sample. As the shape-controlling agent, DEA plays a crucial role in the formation of {0 0 1} facets. N and La co-doping could produce a synergistic effect. N doping can narrow the band gap of anatase TiO2 and increase the utilization efficiency of visible light, while La doping can enhance the separation efficiency of photo-induced electrons and holes. N and La co-doped TiO2 nanosheets exhibited higher visible light photocatalytic activity compared with P25, N doped TiO2 nanosheets and N, La co-doped TiO2 nanoparticles with the same doping concentration. In addition, N and La co-doped TiO2 nanosheets showed well recycling performance.

Cover Feature: High Visible Light Photocatalytic Activity of SnO2‐x Nanocrystals with Rich Oxygen Vacancy (Eur. J. Inorg. Chem. 42/2021)

The Cover Feature shows a tin oxide photocatalyst with strong visible light catalytic performance. By controlling the ratio of Sn4+ to Sn2+, SnO2−x nanocrystals with controllable oxygen vacancies were synthesized. Due to the presence of in-plane oxygen defects, the valence band moves up and the band gap can be narrowed, which result in the high visible light harvesting and the excellent photocatalytic activity. The result indicates that the photocatalytic performance of SnO2−x nanocrystals can be tuned by controlling the oxygen vacancy. More information can be found in the Full Paper by H. Zhan and co-workers.

High Visible Light Photocatalytic Activity of SnO2‐x Nanocrystals with Rich Oxygen Vacancy

AbstractSnO2‐x nanocrystals were prepared using a simple hydrothermal method by controlling the proportions of Sn4+/Sn2+ precursors. Due to the doping of Sn2+, the oxygen vacancies could be introduced into SnO2 nanocrystals, and their concentration can be controlled by the amount of doping Sn2+. The structural characteristics of SnO2‐x nanocrystals was investigated by X‐ray diffraction, Fourier transform infrared spectra, Raman spectra, UV‐vis diffuse reflectance, photoluminescence spectra and X‐ray photoelectron spectroscopy. The results reveal that the bridging O‐vacancies are dominant in the pure SnO2 while the in‐plane O‐vacancies play a key role in the SnO2‐x. Meanwhile, the higher Sn2+ concentration, the more structural disorder was produced. According to XPS analysis, the presence of oxygen defects will change the electronic structure of SnO2‐x nanocrystals, which will lead to the valence band moving up and the smaller band gap. The rich oxygen vacancies, the structural disorder and the narrow band gap should greatly improve the visible light harvesting, and result in the excellent photocatalytic activity.