SnO2 Catalysts Research Articles

Influence of the target product on the electrochemical reduction of diluted CO2 in a continuous flow cell

To date, research on CO2 reduction is almost exclusively performed with pure CO2 while exhaust streams often contain low concentrations of CO2. Direct usage of flue gases avoids the energy intensive CO2 capture step before utilization. This study compares the production of CO and formate on Ag and SnO2 catalysts respectively in order to find the most suitable target product for N2-diluted feed streams. Initial product selectivity screening for different CO2 feed stream compositions was performed at 100 mA/cm2. Excessive hydrogen evolution emerged below 40 % CO2 for the silver catalyst while SnO2 maintained a Faradaic efficiency to formate > 70 % even at 10 % CO2. Both catalysts were further tested at current densities up to 300 mA/cm2 and show a shift of hydrogen evolution onset to more concentrated CO2 streams. These results indicate that formate production is more interesting when utilizing N2-diluted CO2 feed streams compared to CO production.

Structure of Atomically Dispersed Pt in a SnO2 Thin Film under Reaction Conditions: Origin of Its High Performance in Micro Electromechanical System Gas Sensor Catalysis.

A battery-driven micro electromechanical system (MEMS) gas sensor has been developed for household safety when using natural gas. The heart of the MEMS gas sensor is a 7.5 at % Pt-SnO2 thin film catalyst deposited on the SnO2 sensor layer. The catalyst enhances the sensitivity to methane, though its structure under working conditions is unclear. In this study, in situ XAFS was applied to a 7.5 at % Pt-SnO2 catalyst layer deposited on a Si substrate, and we demonstrated that atomically dispersed Pt maintains its lattice position in SnO2 with a small loss of surrounding lattice oxygen in the presence of 1% CH4 and a more reducing gas of 1% H2 at the reaction temperature (703 K), i.e., no Pt aggregation is observed. The lost oxygen is easily recovered by re-oxidation by air. This work has revealed that the atomically dispersed Pt in the SnO2 lattice is the active structure and it is stable even under reaction conditions, which guarantees a long lifetime for the gas sensor.

CO2 utilization and sequestration in Reservoir: Effects and mechanisms of CO2 electrochemical reduction

Owing to the harmful consequences of the greenhouse effect, mankind has reached a consensus to reduce CO2 emissions. CO2 utilization and sequestration is considered the most feasible solution for realizing an effective and economical sequestration of CO2. Herein, CO2-enhanced oil recovery (EOR) is a representative strategy owing to its tremendous sequestration capacity and reasonable economic viability. However, the low sequestration stability and the accompanying secondary disasters have hindered its wider application. Considering this, a novel CO2 utilization and sequestration technology, i.e., CO2 electrochemical reduction (CO2RR)-EOR technology was proposed and its effects and mechanisms were studied. First, a SnO2 catalyst that can be used in the coreflooding experiments was synthesized and its efficiency on CO2RR was evaluated. Then, coreflooding experiments using the SnO2 catalyst were conducted to study the influence of CO2RR on the CO2 sequestration and oil recovery. Next, contact angle and interfacial tension were measured to analyze the effect of the CO2RR on the CO2-crude oil-brine-rock interaction. Finally, the CO2RR-EOR mechanism was proposed. Multiple experiments revealed that the low-cost and easy-synthesis SnO2 catalyst, which was characterized by the 3-dimensioned hierarchical and porous structure, was in the high efficiency and strong stability. Coreflooding results illustrated that the CO2RR remarkably enhanced CO2 sequestration and oil recovery. At the optimal cell potential of 3.75 V, the CO2 sequestration efficiency and oil recovery were as high as 75.93% and 43.8%, respectively, which are much higher than those (50.56% and 37.9%, respectively) achieved in conventional CO2 flooding. Contact angle and interfacial tension results indicated that the CO2RR has a significant impact on the CO2-crude oil-brine-rock interaction. At the optimal cell potential, the crude oil-contact angle and the interfacial tension were 36.2° and 8.9 mN/m, respectively, which are much lower than those (64.6° and 16.4 mN/m, respectively) achieved in conventional CO2 flooding; the CO2-contact angle was 52.2°, which too is much larger than that (31.7°) achieved in conventional CO2 flooding. In this technology, the CO2RR converts the injected CO2 into formate to sequestrate itself, and meanwhile alters the CO2-crude oil-brine-rock interactions, resulting in enhanced CO2 wettability and consequently increases CO2 trapping and retention; causing the weakened oil wettability and the enhanced oil-brine interaction, and finally enhances oil recovery. CO2RR-EOR can be a novel, efficient, and economically-viable CO2 utilization and sequestration technology, which provide a feasible option for the future industrial CO2 emission reduction.

Probing the role of surface speciation of tin oxide and tin catalysts on CO2 electroreduction combining in situ Raman spectroscopy and reactivity investigations

Electrochemical CO2 reduction to formate is a promising approach to store renewable electricity and utilize CO2. Tin oxide catalysts are efficient catalysts for this process, while the mechanisms underneath, especially the existence and role of oxidized tin species under CO2 electroreduction conditions remain unclear. In this work, we provide strong evidence on the presence of oxidized tin species on both SnO2 and Sn during CO2 reduction via in situ surface-enhanced Raman spectroscopy, while in different nature. Reactivity measurements show similar activity and selectivity to formate production on SnO2 and Sn catalysts. Combined analysis of Raman spectra and reactivity results suggests that Sn(IV) and Sn(II) oxide species are unlikely the catalytic species in CO2 electroreduction to formate.

Synthesis and characterization of novel chlorinated SnO2 nanomaterials for biodiesel production via stearic acid esterification with methanol

Up to now the chlorinated SnO2 (xClSnOAmmonia) as solid acid catalysts for stearic acid esterification have not been reported in the literature. Non-chlorinated SnO2 catalysts were prepared by precipitation method using different precipitating agents (ammonium hydroxide, SnOAmmonia, sodium carbonate, SnOCarbonate, and urea, SnOUrea). The impact of different precipitation agents and chloride ion (Cl¯) doping on physicochemical properties of SnO2 were studied by XRD, HR-TEM, BET and NH3-TPD analyses. The surface parameters of SnO2 catalyst were varied with changing the precipitant agent and Cl¯ ion doping. The total acidity of SnOAmmonia was about 32 % and 64 % larger than SnOCarbonate and SnOUrea, respectively. Furthermore, the chlorinated SnO2 with the highest Cl¯ ion loading (0.30ClSnOAmmonia) exhibited a noteworthy increase in total acidity as compared to non-chlorinated SnO2.The catalytic activity of the non-chlorinated catalysts increased gradually as a following order SnOUrea < SnOCarbonate < SnOAmmonia. Noteworthy, the chlorinated catalysts demonstrated progressively enhancements in the activity as increasing Cl¯ ion loadings.

Ordered WOx/mesoporous SnO2 catalysts with excellent acetalization performance for producing bio-additives from glycerol

• Highly ordered mesoporous WOx/SnO2 catalysts have been applied to the glycerol acetalization reaction. • Mesoporous WOx/SnO2 catalysts exhibited excellent catalytic performance in batch-type and continuous flow-type processes for catalytic synthesis of solketal from glycerol. • In a batch type process, 100% glycerol conversion and a solketal yield of 97.4% were achieved. Highly ordered WO x /mesoporous SnO 2 (WO x /meso‑SnO 2 ) catalysts with varying WO x loadings of (5 ∼ 20) wt% displaying excellent catalytic performance were demonstrated in the acetalization of glycerol with acetone. The synthesized catalysts were analyzed using various techniques including X-ray diffraction, N 2 -isotherm, electron microscopy, H 2 temperature programmed reduction, raman spectroscopy, and thermogravimetric analysis. For the acetalization of glycerol with acetone, the most active catalyst was found to be WO x /meso‑SnO 2 with 20 wt% WO x , and the maximum conversion of glycerol (100%) was obtained after 2 h at 20 °C, providing 97.4% selectivity (97.4% yield) for the five-membered product (solketal), due to the presence of a large number of acidic sites on the surface of the catalyst. The catalytic activity of 20 wt% WO x /meso‑SnO 2 was also studied in a flow reactor. Tests were carried out at 30 °C, acetone/glycerol=30, WHSV=(4 or 8) h − 1 , and atmospheric pressure for 24 h. The catalytic results showed that, when the WHSV was 4 h − 1 , after 24 h of time-on-stream, both the glycerol conversion of (100 to 97.9)% and solketal yield of (97.5 to 93.6)% slightly decreased. This result suggests the potential of the 20 wt% WO x /meso‑SnO 2 catalyst for the industrial acetalization of glycerol.

Heterogeneous Fenton process with Fe(III) based catalyst for treatment of textile industry wastewater

In this study, colour and chemical oxygen demand (COD) removal from the textile wastewater by heterogeneous Fenton process have been investigated. Primarily, the Fe(III)/SnO2 catalyst is prepared by co-precipitation method and characterized by BET analyses. The BET analysis results show that the pore size of the Fe(III)/SnO2 catalyst is 2.013 nm and it is classified as a mesoporous catalyst. Then the prepared catalyst is used in the heterogeneous Fenton tests. The effects of the amount of the catalyst, pH of the solution, hydrogen peroxide (H2O2) concentration, temperature and reaction time on the color and COD removals have been studied and the optimum conditions are determined. In the optimum experimental conditions (2.0 g/L of 8 wt.% Fe/SnO2, pH 2, hydrogen peroxide concentration 300 mg/L, temperature 35C and reaction time 90 min), 91% colour and 86% COD removal efficiencies are obtained. The COD removal kinetics of textile wastewater is also investigated. It is determined that the removal of COD obeyed the second-order kinetics. Finally, stability and reuse of the catalyst are tested. This catalyst can be successfully used repeatedly and suitable for textile wastewater treatment

Synthesis of SnO2 Using Hydrothermal Method and Its Application as Catalyst in Esterification of Oleic Acid

Biodiesel is currently getting great attention because it can reduce carbon dioxide emissions by 78.5% compared to petroleum-based diesel. The reaction that can produce biodiesel is the esterification reaction with the addition of a heterogeneous catalyst, one of which is SnO2 which can be used as Lewis acid for the esterification reaction. In our study, SnO2 has been successfully synthesized and then succeeded in reducing the level of oleic acid FFA (Free Fatty Acid) through an esterification reaction. SnO2 was synthesized from SnCl2.2H2O using the hydrothermal method with the addition of CTAB (Cetyl Trimethyl Ammonium Bromide) as a capping agent which was then analyzed using XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscopy). The catalytic activity of the SnO2 sample was carried out through the esterification reaction of oleic acid in ethanol at 65 °C for 6 hours with variations in catalyst weight and variations in the ethanol mole ratio. From XRD analysis, SnO2 sample consists of cassiterite minerals and has typical peaks at 2θ = 26.56°; 33.84°; 37.92°; 38.90°; 42.53°; 51.64°; 54.66°; 57.76°; 61.68°; 62.34°; 64.60°; and 65.88° with the highest intensity at 2θ = 33.84°. During condition optimization of esterification reaction of oleic acid, variations in the weight of SnO2 catalyst resulting from the optimum FFA level could be reduced by 75.05%, whereas to variations in the mole ratio of ethanol, the optimum FFA level could be reduced by 85.53%. In our study, SnO2 has been successfully synthesized and then succeeded in reducing the level of oleic acid FFA through esterification reaction until 85.53%.

Tuning selectivity of electrochemical reduction reaction of CO2 by atomically dispersed Pt into SnO2 nanoparticles

Electrochemical reduction of CO2 into fuels offers an attractive approach to environmental and energy sustainability. Herein, we designed atomically dispersed Pt into SnO2 catalyst (Pt atom/SnO2). Such catalyst dramatically improves the adsorption performance of CO2 and lowers the activation energy of CO2. DFT calculations indicate that the doping of Pt in SnO2 could induce charge redistribution and tune active electronic state, showing higher adsorption energy for intermediates CO2*, HCOO* and HCOOH*, which is different from the Pt NPs loaded SnO2 mainly for H2 generation. As a result, a higher Faradaic efficiency (82.1 ± 1.4%) and the production rate (5105 μmol h−1 cm−2) of HCOO– are achieved at −1.2 V vs. RHE. Moreover, the current density and Faradaic efficiency of HCOO– nearly remain unchanged in 8 h on the Pt atom/SnO2, indicating its high stability. This work opens up a new avenue to tune product selectivity by atomically dispersed catalysts.

Comparison of Pt and Pd anode catalysts supported on nanocrystalline Ru–SnO2 for ethanol oxidation in fuel cell applications

The article presents promising catalysts, applicable for direct alcohol fuel cells (DAFC) for portable and mobile applications. The goal of this work is development of Pt and Pd catalysts deposited on interactive nanocrystalline Ru doped SnO2 support with improved performance. The structure and the morphology of the prepared metal-oxide catalyst support and Pt and Pd based catalysts were examined using XRPD, SEM/EDX and TEM techniques. Electrocatalytic activities of the prepared Pt or Pd based catalysts were evaluated in both alkaline and acidic conditions. The ethanol oxidation reaction (EOR) was studied using conventional electrochemical techniques. The interactive nature of the novel Ru doped SnO2 catalyst support was confirmed, resulting in the enhancement of the EOR kinetics, in comparison to commercially available catalysts. New and simplified synthetic route applied for preparation of interactive catalyst support was presented with the aim to enable easy scale-up of the catalyst production process. Obtained results on the novel catalysts promise great potential in improving the performance and durability of the DAFC.

Catalytic performance and intermediates identification of trichloroethylene deep oxidation over Ru/3DOM SnO2 catalysts

SnO2 is widely used in catalysis owing to its oxygen vacancies, reducible oxygen species, and acidity. In this work, Ru nanoparticles (NPs) supported on three-dimensionally ordered macroporous (3DOM) SnO2 (xRu/3DOM SnO2, Ru loading (x) = 0.09–1.65 wt%) were fabricated via the polyvinyl alcohol-protected reduction routes, and their catalytic activities were determined for trichloroethylene (TCE) and/or toluene oxidation. It was shown that the 0.98Ru/3DOM SnO2 sample exhibited the best activity and good thermal stability, with the temperature (T90%) and apparent activation energy at a TCE (1000 ppmv) conversion of 90% being 300 °C and 44 kJ/mol at space velocity = 40,000 mL/(g h), respectively. Trichloromethane, carbon tetrachloride, tetrachloroethylene, and trichloroacetaldehyde hydrate were the main intermediates in TCE oxidation. The high catalytic performance of 0.98Ru/3DOM SnO2 was attributed to the presence of hydroxyl groups adsorbed at the oxygen vacancies, strong O2 adsorption ability, good low-temperature reducibility, and strong interaction between Ru NPs and 3DOM SnO2. In addition, a catalytic mechanism over xRu/3DOM SnO2 was proposed under dry and humid conditions. The introduction of H2O could block some of the reaction pathways from inhibiting the production of C2Cl4, reduce formation of some by-products (e.g., CH2Cl2, CH3COOH, and C2H2Cl2), promote removal of the chlorine species, and generate a greater amount of HCl and a smaller amount of Cl2. Furthermore, introducing toluene into the TCE stream could generate smaller amounts of organic chlorine by-products and greater amounts of inorganic chlorine products (HCl and Cl2). We are sure that this work can provide a guideline for the industrial application of supported Ru catalysts in the removal of Cl-containing volatile organic compounds.

Challenges in scale‐up of electrochemical CO2 reduction to formate integrated with product extraction using electrodialysis

AbstractBACKGROUNDThe concept of carbon dioxide (CO2) conversion to formate has attracted increasing interest in recent years and various small‐scale studies are present in the literature. However, upscaling of electrochemical CO2 reduction comes with many challenges and there are very few reports available on it. In this study, we present a scalable three‐chamber reactor system for electrochemical CO2 reduction to formate, a precursor suitable for the production of fuels, pharmaceuticals and fertilizers and its extraction as pure formic acid by electrodialysis.RESULTSThe reactor produced 11.7 g L–1 formic acid in 6 h, i.e. 1.95 g L–1 h–1 at −1.8 V applied potential, 5 mol L–1 KOH as an electrolyte, GDE (gas diffusion electrode) cathode with SnO2 catalyst and Nafion™ 200 membrane. The maximum Faradaic efficiency achieved was 38%. In addition, recovery of the formate is equally important as its production for use as feedstock to form chemicals. We therefore also investigated the extraction of formic acid through conventional electrodialysis (CED) and bipolar membrane electrodialysis (BMED). The formic acid was extracted with 88% recovery using CED and 46% with BMED. Furthermore, BMED resulted in recovery of &gt;95% K+ as base and 12 L pure CO2 for possible recycling to the electrochemical cell.CONCLUSIONWe consider this study to provide essential empirical evidence on factors influencing the scale‐up and subsequent performance of a liquid electrolyte‐based electrochemical CO2 reduction reaction (CO2RR) system to formate and its extraction at scale. However, optimized systems and operating strategies still need further investigation, and constituent materials, particularly in terms of membranes and cathode catalyst, need to be developed. © 2021 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley &amp; Sons Ltd on behalf of Society of Chemical Industry (SCI).

Decolourisation of direct red dye 81 from aqueous solutions by SnO2/H2O2 hybrid process

ABSTRACT The aim of this study was to use tin oxide (SnO2) nanoparticle along with hydrogen peroxide (H2O2) and to evaluate their potential in removing direct red 81 (DR 81) dye from aqueous solution.This study was performed on a laboratory scale in a batch mode. To evaluate the structural properties of SnO2 nanoparticles, X-ray diffraction (XRD), and electron microscopy (SEM) images were used.According to BrunauerEmmettTeller (BET) analysis, the particle size is 10 nm. Laboratory results showed that the DR 81 removal efficiency by SnO2/H2O2 hybrid process reached 97.73% under the conditions including H2O2 concentration of 0.1 mmol/L, SnO2 concentration of 0.12 g, initial dye concentration of 25 mg/L, and pH of 3 after 60 min. DR 81 dye removal efficiency has a direct relationship with an increase in reaction time and SnO2 concentration while there is an inverse relationship between removal efficiency with the increase in pH, hydrogen peroxide concentration, and initial dye concentration.Considering the obtained results, the hydrogen peroxide activated by the SnO2 catalyst has a good ability for removal ofDR 81 dye, and this process can be used to remove DR 81 dye and other anionic dyes from wastewaters containing these pollutants. According to the results of the reaction rate, it can be concluded that the process follows the pseudo-second-order kinetics.

Zn- and Ti-Doped SnO2 for Enhanced Electroreduction of Carbon Dioxide.

The electrocatalytic reduction of CO2 into useful fuels, exploiting rationally designed, inexpensive, active, and selective catalysts, produced through easy, quick, and scalable routes, represents a promising approach to face today’s climate challenges and energy crisis. This work presents a facile strategy for the preparation of doped SnO2 as an efficient electrocatalyst for the CO2 reduction reaction to formic acid and carbon monoxide. Zn or Ti doping was introduced into a mesoporous SnO2 matrix via wet impregnation and atomic layer deposition. It was found that doping of SnO2 generates an increased amount of oxygen vacancies, which are believed to contribute to the CO2 conversion efficiency, and among others, Zn wet impregnation resulted the most efficient process, as confirmed by X-ray photoelectron spectroscopy analysis. Electrochemical characterization and active surface area evaluation show an increase of availability of surface active sites. In particular, the introduction of Zn elemental doping results in enhanced performance for formic acid formation, in comparison to un-doped SnO2 and other doped SnO2 catalysts. At −0.99 V versus reversible hydrogen electrode, the total faradaic efficiency for CO2 conversion reaches 80%, while the partial current density is 10.3 mA cm−2. These represent a 10% and a threefold increases for faradaic efficiency and current density, respectively, with respect to the reference un-doped sample. The enhancement of these characteristics relates to the improved charge transfer and conductivity with respect to bare SnO2.

Degradation study on tin- and bismuth-based gas-diffusion electrodes during electrochemical CO2 reduction in highly alkaline media

This work investigated the degradation of tin – based gas-diffusion electrodes (GDE) and also a promising Bi2O3 GDE in electrochemical CO2 reduction in highly alkaline media which has not been studied before. The contributions of the electrode wetting (or flooding, if excessively) and catalyst leaching on the degradation were analyzed. Therefore, electrochemical impedance spectroscopy was used to monitor the wetted surface area of the GDE in combination with post-mortem analysis of the penetration depth by visualizing the electrolyte’s cation in the GDE cross-section. Furthermore, to reveal a possible degradation of the electrocatalyst, its distribution was mapped in the GDEs cross-section after operation while the catholyte was additionally analyzed via ICP-MS. The results clearly demonstrate that the SnO2 catalyst dissolves in the reaction zone inside the GDE and might be partially redeposited near the GDEs surface. Since the redeposition process occurs only partially a steady loss of catalyst was observed impeding a clear distinction of the two degradation phenomena. Nevertheless, the deterioration of the electrode performance measured as faraday efficiency (FE) of the parasitic hydrogen evolution reaction (HER) qualitatively correlates with the differential double layer capacitance (Cdl). A significant difference of the rate of increase for the hydrogen FE and Cdl can be ascribed to the superposition of both above-mentioned degradation mechanisms. The demonstrated instability of SnO2 contrasts with the behavior of Bi2O3 GDE which is stabilized during CO2 conversion by redeposition of the diluted dissolved species as metallic Bi which is active for the CO2 reduction reaction.

Promotional Effects on NH3-SCR Performance of CeO2–SnO2 Catalysts Doped by TiO2: A Mechanism Study

A novel Ti-doped Ce– Sn mixed oxide (Ce–Sn–Ti) catalysts were developed for the selective catalytic reduction (SCR) of NOx with NH3. The addition of titanium could improve SCR activity at a low-temperature window. By optimizing the element proportions, the NOx conversion of Ce0.6Sn2.4Ti2 catalysts could reach more than 90% in a wide-operating temperature window (200 –450 °C). The appropriate doping Ti formed Sn–O-Ti, Sn–O-Ce and Ti–O-Ce structures, which could increase the content of Ce3+ through electrons transfer from Sn or Ti to Ce (Ce3+ + Ti4+ ↔ Ce4+ + Ti3+ and 2Ce4+ + Sn2+ ↔ 2Ce3+ + Sn4+). The solid solution structure increased specific surface areas, active sites (Ce3+), and Lewis acid sites over the Ce0.6Sn2.4Ti2 catalysts. According to DRIFTS results, only bidentate nitrate could react with adsorbed NH3 species. However, adsorbed NH3 species could quickly react with the gaseous NO. The NH3-SCR reaction mechanism over Ce0.6Sn2.4Ti2 catalysts mainly followed the Eley –Rideal mechanism. The electron transfer between tin, cerium, and titanium elements led to generate more active sites (Ce3+) used for NH3 and NOx activation/oxidation, which improved SCR activity. The NH3-SCR reaction mechanism over Ce0.6Sn2.4Ti2 catalyst mainly followed the Eley−Rideal mechanism, in which adsorbed NH3 species could quickly react with the gaseous NO to generate N2 and H2O.

Efficient and stable low-temperature CO oxidation over Pt/In–SnO2 composite triggered by abundant oxygen vacancies and adsorption sites

In ion doping can greatly improve the active oxygen migration ability in the Pt/In–SnO2 catalyst, which is beneficial to CO oxidation at low temperature.

Room temperature synthesis of novel worm like tin oxide nanoparticles for photocatalytic degradation of organic pollutants

Herein, we report the synthesis of novel worm like structured SnO2 nanoparticles photocatalysts by chemical precipitation route from sodium stannate in the absence of a precipitating agent. The physico-chemical characteristics of the synthesized SnO2 were studied using powder X-ray diffraction (PXRD), Diffuse Reflectance Spectroscopy (DRS), Photoluminescence (PL), and High resolution transmission electron microscope (HRTEM) studies. PXRD and HRTEM analysis reveals the formation of amorphous SnO2 in the tetragonal crystal structure. XPS and PL characterization affirmed the presence of oxygen defects in SnO2, which could be due to Sn2+ present in the lattices. The optical band gap calculated using Kubelka-Munk method to be 3.8 eV. Photocatalytic studies of the prepared SnO2 catalyst showed 92% of Rhodamine-B (RhB) degradation in 120 min under UV irradiation. The enhanced dye degradation activity is attributed to oxygen defects in the SnO2 catalyst, which are responsible for the enhanced charge separation and inhibition of electron-hole pair recombination by trapping photogenerated electrons.

Characteristics of textile waste water of Bhilwara (Rajasthan) and its photocatalytic bleaching with SnO2 catalyst

During the last decade, Bhilwara has developed into a leading place in the textile industry in India. The water used in textile industry is almost entirely discharged as waste. The effluents are very complex, containing salt, surfactants, ionic metals and their metal complexes, toxic organic chemicals, biocides, and toxic anions, which are harmful to both flora and fauna existing on our planet. Degradation of these non-biodegradable organic compounds is not possible by conventional treatment processes. The analysis of waste water with different quality parameters and photocatalytic bleaching was examined by using UV light in photochemical reactor with SnO2 catalyst.

Controllably Engineering Mesoporous Surface and Dimensionality of SnO2 toward High‐Performance CO2 Electroreduction

AbstractCurrently, the precise control of the architecture and surface of functional materials for high‐performance still remains a great challenge. Here, a feasible approach is presented to synchronously manipulate mesoporous surface and dimensionality of SnO2 catalysts into hierarchically mesoporous nanosheets and nanospheres within one simple reaction system. By adjustment of the hydrophobic chain length of different fluorinated surfactants, 0D SnO2 nanospheres with average size of 165 nm, and 2D SnO2 ulthrathin nanosheets with thickness of 22.5 nm with the distinct dimensionalities are separately obtained (one stone, two birds), both of which are well decorated with ordered mesopore arrays on their surfaces (pore size of 16 nm). The following calcination gave rise to the formation of hierarchically mesopores (5 and 16 nm, respectively) with high crystallization and improved surface area (96.8 m2 g−1). The resultant mesoporous SnO2 nanosheets as catalyst for CO2 electroreduction reaction (CO2 RR) exhibit excellent selectivity, with a high Faraday efficiency (FE) of HCOOH reaching up to 90.0% at −1.3 V and C1 FE of 97.4% at −1.2 V versus reversible hydrogen electrode, as well as long‐term stability, which is among the best performance compared to reported SnO2 materials, thanks to the collective contributions of the unique architecture and mesoporous structure.