Efficient photodegradation of perfluoroalkyl substances under visible light by hexagonal ZnIn2S4 nanosheets.

Perfluoroalkyl substances (PFASs) are typical persistent organic pollutants, and their removal is urgently required but challenging. Photocatalysis has shown potential in PFASs degradation due to the redox capabilities of photoinduced charge carriers in photocatalysts. Herein, hexagonal ZnIn2S4 (ZIS) nanosheets were synthesized by a one-pot oil bath method and were well characterized by a series of techniques. In the degradation of sodium p-perfluorous nonenoxybenzenesulfonate (OBS), one kind of representative PFASs, the as-synthesized ZIS showed activity superior to P25 TiO2 under both simulated sunlight and visible-light irradiation. The good photocatalytic performance was attributed to the enhanced light absorption and facilitated charge separation. The pH conditions were found crucial in the photocatalytic process by influencing the OBS adsorption on the ZIS surface. Photogenerated e- and h+ were the main active species involved in OBS degradation in the ZIS system. This work confirmed the feasibility and could provide mechanistic insights into the degradation and defluorination of PFASs by visible-light photocatalysis.

Unveiling the photocatalytic marvels: Recent advances in solar heterojunctions for environmental remediation and energy harvesting.

In the quest for effective solutions to address Environ. Pollut. and meet the escalating energy demands, heterojunction photocatalysts have emerged as a captivating and versatile technology. These photocatalysts have garnered significant interest due to their wide-ranging applications, including wastewater treatment, air purification, CO2 capture, and hydrogen generation via water splitting. This technique harnesses the power of semiconductors, which are activated under light illumination, providing the necessary energy for catalytic reactions. With visible light constituting a substantial portion (46%) of the solar spectrum, the development of visible-light-driven semiconductors has become imperative. Heterojunction photocatalysts offer a promising strategy to overcome the limitations associated with activating semiconductors under visible light. In this comprehensive review, we present the recent advancements in the field of photocatalytic degradation of contaminants across diverse media, as well as the remarkable progress made in renewable energy production. Moreover, we delve into the crucial role played by various operating parameters in influencing the photocatalytic performance of heterojunction systems. Finally, we address emerging challenges and propose novel perspectives to provide valuable insights for future advancements in this dynamic research domain. By unraveling the potential of heterojunction photocatalysts, this review contributes to the broader understanding of their applications and paves the way for exciting avenues of exploration and innovation.

Facile synthesis of a novel CeCO3OH@(H/C-CdS) catalyst with synergistic effect of heterophase junction and heterojunction for enhanced visible-light photocatalytic degradation efficiency at room temperature.

A new CeCO3OH@(hexagonal/cubic phases-CdS) (CeCO3OH@(H/C-CdS)) composite catalyst was facilely synthesized by a simple microinjection titration-stirring method, in which CdS nanoparticles were dispersed on the surface of CeCO3OH nanolines. The optimal conditions for the preparation of composite catalysts with high photocatalytic performance were determined by single-factor experiments and response surface experiments. Under these conditions, the degradation rate of 30 mL 2.000 g/L rhodamine B (Rh B) by CeCO3OH@(H/C-CdS) in a photocatalytic reaction for 1 h at 25 °C was up to 86.81 % and its degradation rate in a photocatalytic reaction for 150 min was up to 99.62 %. The degradation rate could be maintained above 80 % even after six times recycling. Especially, the photocatalytic degradation efficiency of 2.000 g/L Rh B on the composite catalyst under sunlight and at room temperature for 30 min reached 97.66 %. Meanwhile, the large size of CeCO3OH considerably alleviated the agglomeration of CdS, providing more adsorption and active sites for visible light-mediated degradation of Rh B. Importantly, the Z-scheme charge transfer realized by CdS and CeCO3OH enhanced the efficient separation of photogenerated electrons and holes, and successfully inhibited the recombination of photogenerated electrons with holes. At the same time, owing to the low energy band difference between the two phases of CdS, charge was transferred between the hexagonal and cubic phases, leaving more effective photogenerated charge to participate in the degradation of Rh B. The synergism of the heterophase junction and heterojunction and the presence of oxygen and sulfur vacancies considerably enhanced the degradation performance of the catalyst. Thus, this study provides a new strategy for the modification and enhanced visible-light catalysis performance of CdS-based catalysts.

Efficient chlorination reaction of Pt/RuO2/g-C3N4 under visible light irradiation for simultaneous removal of ammonia and bacteria from mariculture wastewater.

The removal of ammonia nitrogen (NH4+-N) and bacteria from aquaculture wastewater holds paramount ecological and production significance. In this study, Pt/RuO2/g-C3N4 photocatalysts were prepared by depositing Pt and RuO2 particles onto g-C3N4. The physicochemical properties of photocatalysts were explored by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis diffuse reflectance spectrometer (UV-vis DRS). The photocatalysts were then applied to the removal of both NH4+-N and bacteria from simulated mariculture wastewater. The results clarified that the removals of both NH4+-N and bacteria were in the sequence of g-C3N4 < RuO2/g-C3N4 < Pt/g-C3N4 < Pt/RuO2/g-C3N4. This magnificent photocatalytic ability of Pt/RuO2/g-C3N4 can be interpreted by the transfer of holes from g-C3N4 to RuO2 to facilitate the in situ generation of HClO from Cl- in wastewater, while Pt extracts photogenerated electrons for H2 formation to enhance the reaction. The removal of NH4+-N and disinfection effect were more pronounced in simulated seawater than in pure water. The removal efficiency of NH4+-N increases with an increase in pH of wastewater, while the bactericidal effect was more significant under a lower pH in a pH range of 6-9. In actual seawater aquaculture wastewater, Pt/RuO2/g-C3N4 still exhibits effective removal efficiency of NH4+-N and bactericidal performance under sunlight. This study provides an alternative avenue for removement of NH4+-N and bacteria from saline waters under sunlight.

Nanoarchitectonics of vanadium nanoparticles decorated mesoporous carbon nitride in photocatalytic systems: A study on ethylbenzene oxidation reaction.

In this work, we have described the synthesis of vanadium (V) nanoparticles (NPs) anchored on mesoporous graphitic carbon nitride (V@mpg-C3N4) and their uses in photocatalytic ethylbenzene oxidation to the respective acetophenones. The mpg-C3N4 serves as the support for the decoration of V NPs, through a simple impregnation method. Various advanced techniques, such as XRD, UV-vis spectrometry, HRTEM, HAADF-STEM, AC-STEM, elemental mapping, and BET surface area analysis, were employed for the characterization of V@mpg-C3N4. The detailed characterization studies reveal that the V@mpg-C3N4 catalyst has a medium band gap (2.78 eV), a high surface area (76.7 m2g-1), and a mesoporous nature. The V@mpg-C3N4 photocatalysts demonstrated excellent performance in the light-assisted oxidation of ethylbenzene, achieving over 99 % conversion and selectivity for acetophenone in an environmentally friendly solvent (water) using a domestic light source (50 W white light). This developed synthesis strategy will be useful for synthesizing various noble and non-noble metal-based catalysts and their applications in organic transformation and environmental remediation.

How Metarhizium robertsii's mycelial consciousness gets its conidia Zen-ready for stress.

This memoir takes a whimsical ride through my professional adventures, spotlighting my fungal stress research on the insect-pathogenic fungus Metarhizium robertsii, which transformed many of my wildest dreams into reality. Imagine the magic of fungi meeting science and me, a happy researcher, arriving at Utah State University ready to dive deep into studies with the legendary insect pathologist, my advisor Donald W. Roberts, and my co-advisor Anne J. Anderson. From my very first "Aha!" moment in the lab, I plunged into a vortex of discovery, turning out research like a mycelium on a mission. Who knew 18 h/day, seven days a week, could be so exhilarating? I was fueled by an insatiable curiosity, boundless creativity, and a perhaps slightly alarming level of motivation. Years later, I managed to bring my grandest vision to life: the International Symposium on Fungal Stress-ISFUS. This groundbreaking event has attracted 162 esteemed speakers from 29 countries to Brazil, proving that fungi can be both fun and globally fascinating. ISFUS is celebrating its fifth edition in 2024, a decade after its 2014 debut.

Fungal photoinactivation doses for UV radiation and visible light-a data collection.

Nearly two million people die each year from fungal infections. Additionally, fungal crop infections jeopardize the global food supply. The use of 254 nm UVC radiation from mercury vapor lamps is a disinfection technique known to be effective against all microorganisms, and there are surveys of published UVC sensitivities. However, these mainly focus on bacteria and viruses. Therefore, a corresponding overview for fungi will be provided here, including far-UVC, UVB, UVA, and visible light, in addition to the conventional 254 nm UVC inactivation. The available literature was searched for photoinactivation data for fungi in the above-mentioned spectral ranges. To standardize the presentation, the mean log-reduction doses were retrieved and sorted by fungal species, spectral range, wavelength, and medium, among others. Additionally, the median log-reduction dose was determined for fungi in transparent liquid media. Approximately 400 evaluable individual data sets from publications over the last 100 years were compiled. Most studies were performed with 254 nm radiation from mercury vapor lamps on Aspergillus niger, Candida albicans, and Saccharomyces cerevisiae. However, the data found were highly scattered, which could be due to the experimental conditions. Even though the number of individual data sets seems large, many important fungi have not been extensively studied so far. For example, UV irradiation data does not yet exist for half of the fungal species classified as "high priority" or "medium priority" by the World Health Organization (WHO). In addition, researchers should measure the transmission of their fungal suspensions at the irradiation wavelength to avoid the undesirable effects of either absorption or scattering on irradiation results.

Efficient photocatalytic oxidative coupling of amines under visible light using a trioporphyrins-based covalent triazine framework.

Porphyrins-based porous organic polymers were widely used in photocatalytic oxidation under visible light owing to their superiority in the activation of oxygen. In contrast, the efficiency is usually limited due to the fast recombination and slow electron transfer. Herein, we report the use of a trioporphyrins-based covalent triazine framework (Por-CTF) as visible-light-active photocatalyst for the coupling oxidative of amines to imines at room temperature. By incorporating the π-conjugated porphyrin building block led to the enhanced electron transport between molecules, and the extended recombination time of excited electrons. The photocatalytic efficiency of Por-CTF is superior to that of polymer in absence of triazine framework (POP-TSP), which was prepared by radical polymerization using tetra-(4-vinylphenyl) porphyrin as monomer. Por-CTF catalyst presented excellent efficiency for various primary amines and stability. This work provides a reasonable guidance of catalyst molecular structure design for enhancing efficiency in the photocatalytic oxidation.

Visible Light-Induced Polymerization to Access Polyamides.

Visible light-induced polymerization, as a promising and green strategy, is showing great potential in preparing value-added polymers. Herein, a visible light photoredox catalysis method is reported to afford a library of polyamide with high yields (up to 99%) and high molecular weights (Mws) (up to 71 000 g mol-1). Dithioacids and diamines as the monomers, and 9-mesityl-10-methylacridinium tetrafluoroborate (Mes-Acr-MeBF4) as the organic photoredox catalyst give the polyamides with structural diversity in air under mild conditions without extra metal, base, or additives.

Visible-Light-Induced Hydrogen Generation from Mixtures of Hydrogen Boride Nanosheets and Phenanthroline Molecules.

Hydrogen boride (HB) nanosheets are recognized as a safe and lightweight hydrogen carrier, yet their hydrogen (H2) generation technique has been limited. In the present study, nitrogen-containing organic heterocycles are mixed with HB nanosheets in acetonitrile solution for visible-light-driven H2 generation. After exploring various nitrogen-containing heterocycles, the mixture of 1,10-phenanthroline molecules (Phens) and HB nanosheets exhibited significant H2 generation even under visible light irradiation. The quantum efficiency for H2 generation of the mixture of HB nanosheets and Phens is 0.6%. Based on spectroscopic and electrochemical analyses and density functional theory (DFT) calculations, it is determined that radical species generated from Phens with electrons and protons donated by HB nanosheets are responsive to visible light for H2 generation. The HB nanosheets/Phens mixture presented in this study can generate H2 using renewable energy sources such as sunlight without the need for complex electrochemical systems or heating mechanisms and is expected to serve as a lightweight hydrogen storage/release system.

Asynchronous Code Division Multiplexing-Based Visible Light Positioning and Communication Network Using Successive Interference Cancellation Decoding.

In the evolving landscape of sixth-generation wireless communication, the integration of visible light communication (VLC) and visible light positioning (VLP), known as visible light positioning and communication (VLPC), emerges as a pivotal technology. This study addresses the challenges of asynchronous code division multiplexing (ACDM) in VLPC networks, focusing on the enhancement of data transmission quality and positioning accuracy. Firstly, we propose an orthogonal pseudo-random code (OPRC) for ACDM-based VLP systems. Leveraging its excellent correlation properties, VLP signals preserve orthogonality even amidst asynchronous transmissions, achieving sub-centimeter average positioning errors. Next, by combining OPRC with successive interference cancellation decoding (SICD), we propose an enhanced ACDM-based VLPC system that utilizes OPRC for improved signal orthogonality and SICD for progressive elimination of multiple access interference (MAI) among VLPC signals. The results show substantial improvements in bit-error rate (BER) and positioning error (PE), approaching the performance levels observed in synchronized VLPC systems. Specifically, the SICD-OPRC scheme reduces average BER to 4.3 × 10-4 and average PE to 2.7 cm, demonstrating its robustness and superiority in complex asynchronous scenarios.

Optoelectronics Interfaces for a VLC System for UHD Audio-Visual Content Transmission in a Passenger Van: HW Design.

This work aims to provide the hardware (HW) design of the optoelectronics interfaces for a visible-light communication (VLC) system that can be employed for several use cases. Potential applications include the transmission of ultra-high-definition (UHD) streaming video through existing reading lamps installed in passenger vans. In this use case, visible light is employed for the downlink, while infrared light is used for the uplink channel, acting as a remote controller. Two primary components -a Light Fidelity (LiFi) router and a USB dongle-were designed and implemented. The 'LiFi Router', handling the downlink channel, comprises components such as a visible Light-Emitting Diode (LED) and an infrared receiver. Operating at a supply voltage of 12 V and consuming current at 920 mA, it is compatible with standard voltage buses found in transport vehicles. The 'USB dongle', responsible for the uplink, incorporates an infrared LED and a receiver optimized for visible light. The USB dongle works at a supply voltage of 5 V and shows a current consumption of 1.12 A, making it well suited for direct connection to a universal serial bus (USB) port. The bandwidth achieved for the downlink is 11.66 MHz, while the uplink's bandwidth is 12.27 MHz. A system competent at streaming UHD video with the feature of being single-input multiple-output (SIMO) was successfully implemented via the custom hardware design of the optical transceivers and optoelectronics interfaces. To ensure the system's correct performance at a distance of 110 cm, the minimum signal-to-noise ratio (SNRmin) for both optical links was maintained at 10.74 dB. We conducted a proof-of-concept test of the VLC system in a passenger van and verified its optimal operation, effectively illustrating its performance in a real operating environment. Exemplifying potential implementations possible with the hardware system designed in this work, a bit rate of 15.2 Mbps was reached with On-Off Keying (OOK), and 11.25 Mbps was obtained with Quadrature Phase Shift Keying (QPSK) using Orthogonal Frequency-Division Multiplexing (OFDM) obtaining a bit-error rate (BER) of 3.3259 × 10-5 in a passenger van at a distance of 72.5 cm between the LiFi router and the USB dongle. As a final addition, a solar panel was installed on the passenger van's roof to power the user's laptop and the USB dongle via a power bank battery. It took 13.4 h to charge the battery, yielding a battery life of 22.3 h. This characteristic renders the user's side of the system entirely self-powered.

Selective and stable visible-light-prompted scavenger-free photoelectrochemical strategy based on a ternary ErVO4/P@g-C3N4/SnS2 nanocomposite for the detection of lead ions in different water samples.

Lead ions (Pb2+) are heavy metal environmental pollutants that can significantly impact biological health. In this study, the synthesis of a ternary nanocomposite, ErVO4/P@g-C3N4/SnS2, was achieved using a combination of hydrothermal synthesis and mechanical grinding. The as-fabricated photoelectrochemical (PEC) sensor was found to be an ideal substrate for Pb2+ detection with high sensitivity and reliability. The ErVO4/P@g-C3N4/SnS2/FTO was selected as the substrate because of its remarkable and reliable photocurrent response. The Pb2+ sensor exhibited a low detection limit of 0.1 pM and a broad linear range of 0.002-0.2 nM. Moreover, the sensor exhibited outstanding stability, selectivity, and reproducibility. In real-time applications, it exhibited stable recovery and a low relative standard deviation, ensuring reliable and accurate measurements. The as-prepared PEC sensor was highly stable for the detection of Pb2+ in different water samples. This promising characteristic highlights its significant potential for use in the detection of environmental pollutants.

Visible-Light-Driven Solid-State Fluorescent Photoswitches for High-Level Information Encryption.

Developing visible-light-driven fluorescent photoswitches in solid state remains an enormous challenge in smart materials. Such photoswitches are obtained from salicylaldimines through excited-state intramolecular proton transfer (ESIPT) and subsequent cis-trans isomerization strategies. By incorporating a bulky naphthalimide fluorophore into Schiff base, three photoswitches achieve dual-mode changes (both color and fluorescence) in the solid state. In particular, the optimal one generates triple fluorescence changing from green, to yellow and finally orange upon visible light irradiation. This switching process is fully reversible and can be repeated at least 10 times without obvious attenuation, suggesting its superior photo-fatigue resistance. Mechanism studies reveal that naphthalimide group not only enables the tuning of multicolor with an additional emission, but also induces a folded structure, reducing molecular stacking and facilitating ESIPT and cis-trans isomerization. As such, photopatterning, ternary encoding and transient information recording and erasing are successfully developed. The present study provides a reliable strategy for visible-light-driven fluorescent photoswitches, showing implications for advanced information encryption materials.

Visible-light enhanced tetracycline degradation via SnO2/TiO2-Ni@rGO ternary heterostructures.

This study explores the synthesis, characterization, and photocatalytic performance of a SnO2/TiO2-Ni@rGO nanocomposite for tetracycline (TC) degradation under visible light irradiation. The nanocomposite was precisely designed to enhance structural stability, charge transfer efficiency, and catalytic activity. X-ray diffraction (XRD) analysis confirmed the structural integrity of the SnO2/TiO2-Ni@rGO composite, demonstrating excellent reusability and resistance to photo-corrosion after multiple cycles. Photocatalytic experiments revealed that the SnO2/TiO2-Ni@rGO nanocomposite significantly outperformed individual SnO2/TiO2-Ni and rGO catalysts, achieving a remarkable 94.6% degradation of TC within 60 min. The degradation process followed pseudo-first-order kinetics, with a rate constant (k) of 0.046 min-1. The Z-scheme charge transfer mechanism facilitated efficient separation and migration of photogenerated charge carriers, generating reactive oxygen species such as superoxide (•O2 -) and hydroxyl (•OH) radicals crucial for the oxidation of TC. Radical scavenger studies confirmed that superoxide and hydroxyl radicals were the primary active species. The SnO2/TiO2-Ni@rGO composite also exhibited excellent reusability, maintaining high catalytic performance over four consecutive cycles. These findings suggest that the SnO2/TiO2-Ni@rGO nanocomposite is a promising candidate for the efficient and sustainable photocatalytic degradation of persistent organic pollutants like TC, offering significant potential for environmental remediation applications.

Photocatalytic fluoroalkylation by ligand-to-metal charge transfer.

Trifluoromethyl (CF3) and other fluoroalkyl groups are of great significance in the fields of pharmaceutical chemistry and agricultural chemicals. Fluoroalkyl acids, especially trifluoroacetic acid (TFA) is considered the most ideal fluoroalkylation reagent due to its low cost and easy availability. However, the extremely high oxidation potential requirement of TFA limits its wide application. In recent years, since visible-light-induced fluoroalkylation through the ligand-to-metal charge transfer (LMCT) process can overcome the above limitations, it has become an effective synthetic tool for the construction of fluorinated compounds with complex molecules and structures. In this review, according to the classification of different metal catalysts, we summarize the trifluoromethylation and fluoroalkylation of olefins, heteroaromatics, and terminal alkynes in different metal catalytic systems and their corresponding reaction mechanisms. The photocatalytic fluoroalkylation via LMCT is believed to expedite the development of fluoro-containing drugs, and more novel fluoroalkylation methologies using this strategy will be disclosed.

Modeling and Performance Study of Vehicle-to-Infrastructure Visible Light Communication System for Mountain Roads.

Visible light communication (VLC) is considered to be a promising technology for realizing intelligent transportation systems (ITSs) and solving traffic safety problems. Due to the complex and changing environment and the influence of weather and other aspects, there are many problems in channel modeling and performance analysis of vehicular VLC. Unlike existing studies, this study proposes a practical vehicle-to-infrastructure (V2I) VLC propagation model for a typical mountain road. The model consists of both line-of-sight (LOS) and non-line-of-sight (NLOS) links. In the proposed model, the effects of vehicle mobility and weather conditions are considered. To analyze the impact of the considered propagation characteristics on the system, closed-form expressions for several performance metrics were derived, including average path loss, received power, channel capacity, and outage probability. Furthermore, to verify the accuracy of the derived theoretical expressions, simulation results were presented and analyzed in detail. The results indicate that, considering the LOS link and when the vehicle is 50 m away from the infrastructure, the difference in channel gain between moderate fog and dense fog versus clear weather conditions is 1.8 dB and 3 dB, respectively. In addition, the maximum difference in total received optical power between dense fog conditions and clear weather conditions can reach 76.2%. Moreover, under clear weather conditions, the channel capacity when vehicles are 40 m away from infrastructure is about 98.9% lower than when they are 10 m away. Additionally, the outage probability shows a high correlation with the threshold data transmission rate. Therefore, the considered propagation characteristics have a significant impact on the performance of V2I-VLC.

Clay Nanosheet-Based Nanocomposite Supramolecular Hydrogel Enabling Rapid, Reversible Phase Transition Only with Visible Light.

High mechanical properties and rapid sol/gel phase transition are mutually exclusive in the hydrogels reported to date, most likely because the 3D crosslinked networks of mechanically robust hydrogels comprise bundled thick fibers that are not rapidly dissociable or formable.  Herein, we report a visible light-responsive hydrogel that showed a rapid, reversible sol/gel phase transition despite its relatively high mechanical properties (storage modulus ~1000 Pa).  To construct its 3D crosslinked network, we used a design strategy analogous to that employed for our highly water-rich yet mechanically robust nanocomposite supramolecular hydrogel ("aqua material").  In this case, multiple poly(ethylene glycol) chains carrying ortho-tetramethoxyazobenzene termini (AzoPEG) were noncovalently crosslinked by clay nanosheets (CNSs) with surface-immobilized ß-cyclodextrin units using their seven guanidinium ion (Gu+) pendants (GuCD) via a multivalent salt-bridge.  When exposed to visible light at 625 and 450 nm, the azobenzene termini isomerized from trans-to-cis and cis-to-trans, respectively, and were detached from and attached to the surface-immobilized GuCD units.  The advantage of this CNS-based nanocomposite supramolecular system is its simple 3D network structure, which forms and breaks rapidly without slow chain entangling and disentangling processes.

Gadolinium doped carbon dots for anti-gram-negative bacteria and visible light photodynamic enhancement of antibacterial effect.

Infection with gram-negative bacteria is the main source of the most serious infectious pathogens. Developing new antibacterial materials that break through their external membranes and stay in the bacterial body to result in an antibacterial effect is the key to achieving high efficiency against Gram-negative bacteria. A Gd-doped carbon dot (GRCD) was prepared using the approved therapeutic diagnostic agents Rose Bengal (RB) and gadolinium ions (Gd3+), which was used to resist Gram-negative bacteria (e.g. E. coli, Escherichia coli). GRCD not only showed strong antibacterial activity by destroying the external membranes of E. coli (inhibition rate against E. coli was 92.0 % at 20 µg/mL) but also bound to E. coli DNA and generated single oxygen (1O2) (quantum yield was 0.50) through visible light-driven catalysis, thus decomposing the DNA of E. coli and further enhancing the antibacterial performance of GRCD. Under visible light conditions, the inhibition rate against E. coli reached 95.8 % at a low concentration of 2.5 µg/mL, without obvious cytotoxicity to NIH3T3 cells. The use of GRCD in treating wound infections in mice caused by E. coli was quite good, without side reactions on the mice's essential organs. In this study, a new approach has been provided to the design and synthesis of carbon dot nanocomposites for use against Gram-negative bacteria.

Influence of Pd, Pt and Au nanoparticles in the photocatalytic performance of N-TiO2 support under visible light.

In this article, we report the modification and photocatalytic evaluation of commercial TiO2-P25 under visible light for methyl orange (MO) dye degradation under visible light. The activity of materials doped with N, Pd, Pt and Au on to the TiO2-P25 was evaluated, with optimal photocatalytic performance achieved using Au nanoparticles doped on an N-functionalized titania surface. X-ray diffraction (XRD), physical nitrogen adsorption/desorption isotherm curves, transmission electron microscopy (TEM), diffuse reflectance spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to study the structural and textural properties of the samples. The chemical species present in the bulk and surface of the catalysts were identified using X-ray photoelectron spectroscopy (XPS) and microwave plasma-atomic emission spectroscopy. The results show that Au/N-TiO2 photocatalyst presents a remarkable enhanced activity for MO dye degradation, under visible light illumination, reaching 100% after 4 h. The enhanced photocatalytic activity using this composite is attributable to the well-dispersed and small size of Au nanoparticles, large surface area, reduction of band-gap energy and the interaction between nitrogen and Au which promoted a synergistic effect. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'.