Indoor VOCs Research Articles

Enhanced performance of photocatalytic oxidation of indoor toluene over Pd/TiO2 catalyst by tuning surface defect concentrations

An effective approach for the elimination of indoor gaseous toluene through photocatalytic oxidation involves the engineering of surface defects on catalysts. In this study, the concentrations of surface oxygen defects in PdTi-xN (x = 10, 30) catalysts were controlled using the sodium borohydride solid-phase reduction method, and their performances in the photocatalytic oxidation of indoor gaseous toluene were evaluated. PdTi–10 N demonstrated high photocatalytic efficiency for toluene oxidation, achieving 84% toluene conversion and approximately 75% CO2 mineralization. Characterization results indicated that surface oxygen defects can enhance the separation of photo-generated electrons and holes, facilitating their interaction with Pd0 species to form Ti3+ species. More reactive oxygen species (·OH-and ·O2−) were generated on PdTi–10 N due to the synergistic effect of surface oxygen defect and Ti3+ species, which played a significant role as the toluene oxidation. This work provides a new insight for the design and development of high-performance Pd/TiO2 catalysts in the field of indoor VOCs treatment.

Oxygen-deficient WO3 for stable visible-light photocatalytic degradation of acetaldehyde within a wide humidity range

Indoor VOCs pollution has attracted broad attention for its harm to mankind’s health recent years. Photocatalytic degradation of indoor VOCs holds great prospects in addressing these health concerns in daily life. However, traditional photocatalysts have a large recombination rate of charge carriers and a decrease of the photocatalytic degradation efficiency under high relative humidity. Herein, uniform tungsten oxide nanoparticles with enriched oxygen vacancies (WO3-U) were synthesized by a direct annealing method with urea addition, which exhibited superior performance in the visible-light photocatalysis. The reaction rate constant value of photocatalytic acetaldehyde degradation over WO3-U catalyst was above 3 times higher than that of pristine WO3 sample. More importantly, the WO3-U catalyst maintained stable and excellent photocatalytic performance at relative humidity range of 25–100 %. Except for the enhanced photogenerated charges separation, abundant oxygen vacancies could effectively accelerate O2 activation to generate •O2−, which accounted mainly for the initial conversion of acetaldehyde. Then the subsequent transformation of •O2− into •OH to promoted the final mineralization of acetaldehyde. In addition, the presence of oxygen vacancies also facilitated H2O dissociation to form surface hydroxyl groups, which increased the adsorption of acetaldehyde, resulting in the consistent photocatalytic performance of WO3-U catalyst within a wide humidity range. This work provides guidelines to design visible-light responsive photocatalysts with efficient activity at high humidity conditions for indoor VOCs degradation.

Construction of CdS@g–C3N4 heterojunction photocatalyst for highly efficient degradation of gaseous toluene

Exploring efficient photocatalysts for the degradation of VOCs under visible light is a challenge. CdS@g–C3N4 heterojunction photocatalytic materials were developed in this study using a microwave-assisted sol-gel process. CdS@g–C3N4(0.2) photocatalyzed the maximum degradation of gaseous toluene under visible light irradiation, and the time required to achieve the same degradation rate was reduced by 270 min when compared to pure CdS. The morphological characterization, photoelectric property analysis, and DFT calculations all verified that the CdS nanoparticles were uniformly disseminated on the surface of g–C3N4, and that the interfaces were closely contacted to form a heterojunction interface with a built-in field. This enhances charge transfer from CdS to g–C3N4 while successfully decreasing electron-hole pair recombination caused by light. Furthermore, the energy band structure was altered to absorb longer wavelengths of light and extend the absorption spectral range, improving the photocatalytic material's efficacy for broad-spectrum light such as sunshine. This paper proposes methods for predicting and optimizing the surface structure of catalysts, as well as developing high-performance multi-heterojunction photocatalysts for the degradation of indoor VOCs.

Mixed-ligand based water-stable Mn(II)-MOF for quick, sensitive, and reusable IFE-PET-RET facilitated detection of formaldehyde and Cr(VI)-oxoanions in real-field samples like food and industrial water: experimental and theoretical insights.

We report the luminescence-based detection of Group-1 carcinogen formaldehyde (FA) and Cr(VI)-oxoanions with a mesoporous Mn(II)-MOF (1), featuring a uninodal 4-c net topology and linear 1D square channels forming a polymeric 2D network. The Mn-MOF i.e., [Mn(phen)(hia)(H2O)]∞ was solvothermally constructed using π-conjugated, chelating phenanthroline (phen) and µ3-η2:η1 binding 5-hydroxyisophthalic acid (hia) ligands. The 2D rod-like crystallites of 1 demonstrated excellent phase purity, high thermal and photostability, and robustness under harsh conditions. The SCXRD and XPS studies established the structural framework and elemental composition, while the Hirshfeld surface analysis and NCI-RDG plot confirmed the presence of π-π stacking and weak interactions in 1. We explored the bright-blue emission of 1 for recyclable and fast-responsive (∼70 s) 'turn-off' detection of FA, with a low limit of detection (LOD) of 8.49 µM. Based on this, a 04-input-03-output molecular logic gate was proposed, which can be useful as a molecular switch for future applications. Furthermore, a unique experimental setup using the MOF film demonstrated ∼57% quenching upon exposure to FA vapor (an indoor VOC). Additionally, 1 exemplified itself as an efficient probe towards Cr(VI)-oxyanions, depicting LODs of 79 and 170 ppb, Stern-Volmer constants (KSV) of 16.13 × 104 and 12.73 × 104 M-1, and response times of ∼48 and ∼40 s for CrO42- and Cr2O72-, respectively. DFT calculations and specific wet-chemical investigations elucidated the FA detection to be triggered by photo-induced electron transfer (PET), while the Cr(VI)-sensing involved a combination of PET, the inner-filter effect (IFE), resonance energy transfer (RET), and electrostatic H-bonding interactions. The FA detection was validated using food samples (fish and meat) and wastewater specimens, achieving excellent recovery rates of ∼92-95%. Furthermore, the MOF's efficacy in recognizing the Cr(VI)-species in complex matrices (coal mine wastewater, sewage, and tap water) was investigated to yield high KSV values (3.10-5.17 × 104 and 2.16-7.03 × 104 M-1 for CrO42- and Cr2O72-), which demonstrated the probe's consistency and reliability.

Efficient Exciton Dissociation on Ceria Chelated Cerium-Based MOF Isogenous S-Scheme Photocatalyst for Acetaldehyde Purification.

Long-term exposure to low concentration indoor VOCs of acetaldehyde (CH3CHO) is harmful to human health. Thus, a novel isogenous heterojunction CeO2/Ce-MOF photocatalyst is synthesized via a one-step hydrothermal method for the effective elimination of CH3CHO in this work. This CeO2/Ce-MOF photocatalyst performs well in CH3CHO removal and achieves an apparent quantum efficiency of 7.15% at 420nm, which presents ≈6.7 and 3.4times superior to those generated by CeO2 and Ce-MOF, respectively. The enhanced efficiency is due to two main aspects including i) an effective photocarrier separation ability and the prolonged reaction lifetime of excitons play crucial roles and ii) the formation of an internal electric field (IEF) is sufficient to overcome the considerable exciton binding energy, and increases the exciton dissociation efficiency by up to 50.4%. Moreover, the reasonable pathways and mechanisms of CH3CHO degradation are determined by in situ DRIFTS analysis and simulated DFT calculations. Those results demonstrated that S-scheme heterojunction successfully increases the efficiency of harmful volatile organic compounds elimination, and it offers essential guidance for designing rare earth-based MOF photocatalysts.

Characteristics Analysis of Volatile Organic Compounds Pollution in Residential Buildings in Northeast China Based on Field Measurement

A total of 8 mechanically ventilated residential buildings and 8 naturally ventilated residential buildings were selected to analyze the pollution characteristics of indoor VOCs under different ventilation modes in the severe cold area of northeast China. On typical meteorological days in each season, VOCs were detected on site, and ventilation modes were investigated by long-term online monitoring. The test results showed that the TVOC (total volatile organic compounds) concentrations varied greatly in different seasons or different functional rooms, and the TVOC concentration was the highest in winter, with a value of 0.994 mg/m3. The kitchen was the place with the most serious VOC pollution, and the TVOC concentration could reach 1.403 mg/m3. Benzene series and methylsiloxane had the highest detection rates, but the detected concentrations were low, and the average concentrations were 0.025 mg/m3 and 0.013 mg/m3 respectively. Among the VOC types with a detection rate greater than 50%, the average proportions of aldehydes, alkanes, and benzene series were 18.7%, 15.39%, and 14.38%, respectively. And their mass ratios were also high, which were 14.90%, 30.85%, and 15.70%, respectively. The annual daily average ventilation duration of mechanically ventilated residential buildings was 7.84 h longer than that of naturally ventilated residential buildings. The median TVOC concentrations of mechanically ventilated residential buildings and naturally ventilated residential buildings were 0.621 mg/m3 and 0.707 mg/m3, respectively. The fresh air system was applicable in the severe cold area of northeast China.

S-scheme construction boosts highly active self-supporting CeO2/Cu2O photocatalyst for efficient degradation of indoor VOCs

Photocatalyst-governing degradation of VOCs emitted from household products is promising due to its high performance and long-term durability. In this study, unique hierarchical CeO2/Cu2O nanowire arrays with S-scheme construction grow on a Cu mesh through a simple wet chemical method. Abundant oxygen vacancies on CeO2 work as adsorption sites, and the effective separation of photogenerated carriers driven by built-in electric field in the S-scheme CeO2/Cu2O heterojunction generates mobile reactive oxygen radicals for oxidizing target VOCs. Spectra of Kelvin probe force microscopy (KPFM) reveal that the potential difference at the CeO2/Cu2O interface grows from 9 mV in dark to 29 mV under irradiation, demonstrating a powerful force for driving the migration of photoelectrons. Therefore, under simulated sunlight exposure, 50 ppm of toluene, xylene and formaldehyde can be completely degraded in 70, 50 and 6 min by 15 cm2 CeO2/Cu2O mesh, respectively. The elimination of actual indoor VOCs confirms the practicability of the self-supporting CeO2/Cu2O catalyst, which figures out new ideas for designing efficient photocatalysts for the removal of VOCs pollutants.

In Situ Indoor Air Volatile Organic Compounds Assessment in a Car Factory Painting Line

Proper working conditions must be one of the employers’ main concerns in any type of company but particularly in work locations where the employees are chronically exposed to hazardous compounds, like factories and production lines. Regarding this challenge, the present research addresses the mapping of a car factory painting line to possibly toxic volatile organic compounds emitted by all the coatings and chemicals used during the work shifts for the future evaluation of employees’ exposure. For the first time, a Gas Chromatography–Ion Mobility Spectrometry device was employed for the in situ detection of volatile organic compounds in an automotive factory. A total of 26 analytes were detected at nine different locations, of which 15 VOCs were accurately identified. Pure chemical-grade substances were used for the development of the VOC database. Although quantitative analysis was not the goal of this study, a calibration model was presented to one analyte for exemplificative purposes. Relative intensity profiles were plotted for all locations, revealing that some indoor VOCs can reach intensity levels up to 60 times higher than in outdoor air samples. The achieved results proved that the painting line has an abundant number of VOCs emitted from different sources and may lead to serious health risks for the employees. Additional studies shall be developed in the painting line for quantitative evaluation of the existing VOCs and their influence on the employees’ health conditions.

Indoor Levels of Volatile Organic Compounds at Households in Ulaanbaatar City

Objectives: VOCs, or Volatile Organic Compounds, are a group of organic chemicals that can easily evaporate into the air at room temperature. They are called “volatile” because they have high vapor pressure and can readily form vapors or gases at normal atmospheric conditions. To address this knowledge gap, we aimed to assess VOC exposure and its associated health risks.Method: Samples were collected through the adsorbent tube, followed by detachment from the solvent by organic solvents solvent or methanol, and analyzed by gas chromatographic equipment attached with a flame ionization detector (FID). We selected 150 households from the Chingeltei and Bayangol districts in Ulaanbaatar city, specifically sections 4, 5, 6, and 12, to examine the levels of indoor VOCs in this study. We used the nonparametric Mann-Whitney U test to compare medians of VOC levels for two independent groups. Kruskal-Wallis test was carried out to determine if there was any significant difference between medians of VOC levels for more than two independent groups, including the type of paint used, wooden furniture used, and construction year.Results: We found no significant difference in benzene concentration among different types of households (p<0.8112). The highest benzene concentration (0.181 µg/m3) was measured in apartments and houses. Although there was no statistically significant difference between household room types, the kitchen had a higher benzene concentration than other rooms (p<0.8156). Factors such as household total volume, building construction year, and materials used for floors and walls did not significantly affect indoor benzene concentration. Most of the day, the benzene levels exceeded the standards set by the Indoor Air Quality Act of South Korea and the recommended levels by the Health Minister and Construction and Urban Development Minister of Mongolia. In 133 households in Ulaanbaatar city, indoor VOCs, specifically benzene concentration, exceeded the recommended level stated in Order No. A105/08 by the Health Minister and Construction and Urban Development Minister in 2017.Conclusion: Indoor benzene concentration did not vary significantly based on household type, room type, household volume, building construction year, construction wall material, construction floor material, whether new furniture was purchased or the dwelling was repaired and painted within the last two months, proximity to major roads, or indoor smoking status.

Study on the performance of an ultra-low energy building in the Qinghai-Tibet Plateau of China

The ultra-low energy building is an effective solution to reduce building energy consumption and CO2 emission in high-cold and high-altitude areas of China. A new ultra-low energy building in the Qinghai-Tibet Plateau was built, and a solar-air source heat pump system was designed to cover the heating needs in winter. The performance of the ultra-low energy building was studied by measurement and simulation methods. The measured results show that the average room temperature is above 18 °C without heating, and the indoor temperature can meet the requirements of 20 °C with the heating system. The indoor VOC concentration can be maintained at a low level. The building's air tightness can meet the requirements of the ultra-low energy building. The heating system ran well, and the average COP was 2.6. The simulation results show that the natural room temperature is between 20 and 23 °C more than 90% of the time under heating conditions. The average COP of the heat pump is 3.6, and the solar energy guarantee rate is 44.8% throughout the heating season. The heating system can save 2490.5 kg of standard coal and 6724.3 kg of CO2 emission per year.

Enhanced Photocatalytic Degradation of Indoor Low Concentration Gaseous Formaldehyde by Asymmetric Silveriodate Composited with 2D or 3D Bismuth Oxybromide.

Formaldehyde is one of the most hazardous and typical indoor VOCs air pollutants. Asymmetric AgIO3 was respectively composited with 3D hierarchically structured BiOBr and 2D BiOBr nanosheets to photodegrade gas-phase formaldehyde. Ag/AgIO3 /BiOBr(CMC) demonstrated better photocatalytic performance than Ag/AgIO3 /BiOBr owning to the role of biomass solvent sodium carboxymethyl cellulose in increasing the specific surface area, reducing the band gap and changing the dominant facets. Moreover, Ag nanoparticles coming from the reduction in AgIO3 were confirmed by XRD, SEM and XPS. The surface plasma resonance effect of Ag NPs improved the efficiency of the light quantum. Besides, different exposed facets of {010} in BiOBr(CMC) and {001} in BiOBr resulted in distinct oxygen vacancy structures. could be generated via a two-electron transfer pathway on the {010} dominant facets surface in AABR-CMC, leading to the change in photolysis pathway and facilitating more · OH produced by AABR-CMC. Compared with pure AgIO3 and BiOBr or BiOBr(CMC), the photocatalytic efficiency of the composites was improved significantly. Optimal photodegradation efficiency for HCHO was achieved for AABR-75 and AABR-CMC50.

Research Progress on Indoor VOC Pollution and Control

Abstract: Nowadys, indoor air pollution is harming human health and has become a global problem. Therefore, research on indoor air pollution is necessary. This paper systematically reviews the research progress of indoor air pollution in recent years, mainly including indoor pollutant types and sources, indoor pollutant detection methods and equipment, pollutant release simulation models and quality standards, indoor air treatment technologies, and points out the problems that exist in current researches. Furthermore, it proposes the direction of future research work.

Develop and validate a mathematical model to estimate the removal of indoor VOCs by carbon filters

Adsorption-based air filters, especially carbon-based ones, are usually employed to remove VOCs from indoor air. Conducting tests at ppm level, which is substantially higher than the actual indoor concentration of VOCs, is recommended for reducing the test duration. Consequently, developing a model for estimating the service life of adsorptive filters under actual conditions is imperative.A comprehensive model that considers axially dispersed plug flow for interpellet mass transfer and pore surface diffusion model (PSDM) with variable surface diffusivity for intrapellet mass transfer was used to predict the performance of two filters exposed to three VOCs. First, the results of experiments conducted at concentrations ranging from 9 to 90 ppm in a bench-scale setup were used to compute the Dubinin-Radushkevich (D-R) isotherm parameters, which are concentration-independent. Then, the surface diffusivities at zero loading for various adsorbate-adsorbent systems were determined by fitting the developed model into the results of the experimental data performed at concentrations of 9 ppm or 30 ppm. Finally, the model was validated using experimental data which were conducted at lower concentrations, a higher velocity and on a full-scale setup.The inter-model comparison was carried out by comparing the comprehensive model with four other models to study the importance of various mass transfer steps. Finally, in sensitivity analysis, five dimensionless parameters (Pe, St, Edp, Eds and Dg) were examined to investigate their impact on the filter's efficiency.

The impact of plug-in fragrance diffusers on residential indoor VOC concentrations.

Plug-in fragrance diffusers are one of myriad volatile organic compound-containing consumer products that are commonly found in homes. The perturbing effects of using a commercial diffuser indoors were evaluated using a study group of 60 homes in Ashford, UK. Air samples were taken over 3 day periods with the diffuser switched on and in a parallel set of control homes where it was off. At least four measurements were taken in each home using vacuum-release into 6 L silica-coated canisters and with >40 VOCs quantified using gas chromatography with FID and MS (GC-FID-QMS). Occupants self-reported their use of other VOC-containing products. The variability between homes was very high with the 72 hour sum of all measured VOCs ranging between 30 and >5000 μg m-3, dominated by n/i-butane, propane, and ethanol. For those homes in the lowest quartile of air exchange rate (identified using CO2 and TVOC sensors as proxies) the use of a diffuser led to a statistically significant increase (p-value < 0.02) in the summed concentration of detectable fragrance VOCs and some individual species, e.g. alpha pinene rising from a median of 9 μg m-3 to 15 μg m-3 (p-value < 0.02). The observed increments were broadly in line with model-calculated estimates based on fragrance weight loss, room sizes and air exchange rates.

Partitioning characteristics of indoor VOCs on impermeable surfaces covered by film-phase DnBP and DEHP

PAEs usually adsorb on indoor surfaces to form organic films, which could be more hazardous after enriching VOCs. Two typical PAEs, DnBP and DEHP, in the film phase, were chosen to explore the enrichment capacity of gaseous toluene, hexanol, and benzyl alcohol in this study. Exposed to gaseous VOCs less than 250 ppb, film-phase DnBP and DEHP could capture benzyl alcohol significantly and hexanol slightly from the air, respectively, while toluene was hardly absorbed in the films. Henry's law constants and partition coefficients (K) of VOCs in DnBP or DEHP films were derived, supposing films as dilute solution systems. The K value of VOC in DnBP or DEHP films was 1∼2 orders larger than the octanol-air partition coefficient (Koa), indicating that the surface film composition greatly influences VOC adsorption. Benzyl alcohol was the largest VOC component in surface films, agreeing well with the molecular dynamics simulation results. The hydroxyl and phenyl groups of benzyl alcohol molecules may be key factors in VOC enrichment. They form hydrogen bonds with the ester group and π-π stacking interaction with the phenyl group of DnBP or DEHP molecules, respectively. After enriching VOCs, film-phase PAEs could evoke combined exposure risks to human beings.

Fluorine-induced oxygen vacancies on TiO2 nanosheets for photocatalytic indoor VOCs degradation

Photocatalytic degradation of indoor VOCs has great prospects for addressing human health issues in daily life. Here, TiO2 containing fluorine ions (F−) on the surface was reduced by hydrogen to obtain the oxygen vacancy-rich sample F-TiO2−x, which exhibited excellent performance in the photocatalytic VOCs degradation. The characterization results showed that the strong electron repulsion between F− and Ti3+ encouraged metallization to promote photogenerated charges separation. The DFT calculation results proved that the F− on the surface of TiO2 was beneficial to the formation of surface oxygen vacancies, and the synergistic effect of oxygen vacancies and F− on F-TiO2−x could improve the adsorption and activation of H2O molecules, which was also effective for oxygen molecules. All of these were beneficial to the formation of active free radicals. Moreover, the presence of surface F- could effectively promote the stabilization of oxygen vacancies.

Associations between indoor VOCs and childhood asthma in Shanghai, China: an analysis stratified by frequency of window opening during night

Few studies pay attention to the possible associations between indoor VOCs and childhood asthma in Shanghai considering the effect of household ventilation. From March 2013 to December 2014, we collected air samples from 358 children's bedrooms in Shanghai, China. Information on childhood asthma, environmental exposures, and lifestyle behaviors was collected. Two-sample of Mann-Whitney U test, bivariate logistic regressions, and multiple logistic regression were used to obtain the association between VOCs and childhood asthma. Association analysis stratified by frequency of window opening during night was conducted to explore its possible effect on the target association. High concentrations of toluene and dodecane were significantly associated with childhood wheeze, and a high concentration of toluene was significantly associated with diagnosed asthma. In the bedrooms with low frequency of window opening during night, high concentrations of toluene, dodecane, and TVOC were significantly associated with childhood wheeze, and a high concentration of toluene was significantly associated with diagnosed asthma. Our results indicate that exposure to VOCs may be a risk factor for childhood asthma, especially in the bedrooms with poor ventilation during night. Family avoidance behaviors of household ventilation should be considered in the study of associations of household VOCs with childhood asthmatic symptoms.

Formation of cluster mode particles (1–3 nm) in preschools

This study is the first study that reports the cluster particle (1–3 nm) formation (CPF) in two modern preschools located in Nur-Sultan city of Kazakhstan from October 28 to November 27, 2019. The average particle number concentration and mode diameter values during major CPF events in Preschool I and Preschool II were found to be 1.90 × 106 (SD 6.43 × 106) particles/cm3 and 1.60 (SD 0.85) nm, and 1.11 × 109 (SD 5.46 × 109) particles/cm3 and 2.16 (SD 1.47) nm, respectively. The ultraviolet PM concentration reached as high as 7 μg/m3 in one of the measurement days. The estimated emission rate in Preschool I for CPF events was 9.57 × 109 (SD 1.92 × 109) particles/min. For Preschool II, the emission rate was 7.25 × 109 (SD 12.4 × 109) particles/min. We identified primary cluster particles (CPs) emitted directly from the sources such as candle burning, and secondary CPs formed as a result of the oxidation of indoor VOCs or smoking VOCs. The secondary CPs are likely to be SOA. Indoor VOCs were mainly emitted during cleaning activities as well as during painting and gluing. Indoor VOCs are the controlling factors in the CPF events. Changes in the training and cleaning programs may result in significant reductions in the exposure of the children to CPs.

Assessing the Energy, Indoor Air Quality, and Moisture Performance for a Three-Story Building Using an Integrated Model, Part Two: Integrating the Indoor Air Quality, Moisture, and Thermal Comfort

In this paper, an integrated model that coupled CONTAM and WUFI was developed to assess the indoor air quality (IAQ), moisture, and thermal comfort performance. The coupling method of CONTAM and WUFI is described based on the exchange of airflow rate control variables as infiltration, natural and mechanical ventilation parameters between heat and moisture flow balance equations in WUFI and contaminant flow balances equations in CONTAM. To evaluate the predictions of the integrated model compared to single models of CONTAM and WUFI, four scenarios were used. These scenarios are airtight-fan off, airtight-fan on, leaky-fan off, and leaky-fan on, and were defined for a three-story house subjected to three different climate conditions of Montreal, Vancouver, and Miami. The measures of the simulated indoor CO2, PM2.5, and VOCs obtained by CONTAM; the simulated indoor relative humidity (RH), predicted percentage of dissatisfied (PPD), and predicted mean vote (PMV) obtained by WUFI; and those obtained by the integrated model are compared separately for all scenarios in Montreal, Vancouver, and Miami. Finally, the optimal scenarios are selected. The simulated results of the optimal scenarios with the integrated model method (−28.88% to 46.39%) are different from those obtained with the single models. This is due to the inability of the single models to correct the airflow variables.

Photocatalytic mineralization of indoor VOC mixtures over unique ternary TiO2/C/MnO2 with high adsorption selectivity

Formaldehyde (CH2O) and toluene (C7H8) are typical indoor air pollutants that have high harm to people’s health. Photocatalytic oxidation is a feasible approach, but still remains the problem of incomplete degradation to form refractory intermediates and uncertainty of interaction between multivariant components. This paper used natural proteins from waste shell as the carbon source and template to synthesize the ternary TiO2/C/MnO2 photocatalysts. It exhibited high adsorption selectivity and excellent photocatalytic performance for CH2O and C7H8 mixture mineralization under visible light irradiation. The optimal candidate achieved near completely mineralization within 60 min in the simulated indoor environment and exhibited remarkable stability after 5 cycles. Large amounts of oxygen vacancies, lattice distortions of TiO2, and tailored bandgap structure contributed to these excellent behaviors. Besides, carbon existence as an electron transfer channel dropped the interfacial charge-transfer resistance, thus prolonging the lifetime of charge carriers and making them rapidly go through the surface photo-oxidation reactions. In-situ DRIFTs results indicated that CH2O and C7H8 mixtures possessed the same reaction pathway and rate-determining step with single component. Above all, this paper offered a facile, sustainable, and green approach to synthesize efficient photocatalysts for treating indoor CH2O/C7H8 pollution with visible light irradiation.