Selective Photocatalytic CO2 Reduction Research Articles

Metal–Organic Framework Decorated Cuprous Oxide Nanowires for Long‐lived Charges Applied in Selective Photocatalytic CO2 Reduction to CH4

AbstractImproving the stability of cuprous oxide (Cu2O) is imperative to its practical applications in artificial photosynthesis. In this work, Cu2O nanowires are encapsulated by metal–organic frameworks (MOFs) of Cu3(BTC)2 (BTC=1,3,5‐benzene tricarboxylate) using a surfactant‐free method. Such MOFs not only suppress the water vapor‐induced corrosion of Cu2O but also facilitate charge separation and CO2 uptake, thus resulting in a nanocomposite representing 1.9 times improved activity and stability for selective photocatalytic CO2 reduction into CH4 under mild reaction conditions. Furthermore, direct transfer of photogenerated electrons from the conduction band of Cu2O to the LUMO level of non‐excited Cu3(BTC)2 has been evidenced by time‐resolved photoluminescence. This work proposes an effective strategy for CO2 conversion by a synergy of charge separation and CO2 adsorption, leading to the enhanced photocatalytic reaction when MOFs are integrated with metal oxide photocatalyst.

The synergistic effect of phosphomolybdic acid on rhodium-based metal–organic frameworks for the efficient selective photocatalytic reduction of CO2 to CO

PMA@NH2-MIL-68(Rh) with a mangosteen spherical structure were synthesized by a hydrothermal method and used for the highly efficient selective photocatalytic reduction of CO2 to CO.

Visible light induced selective photocatalytic reduction of CO2 to CH4 on In2O3-rGO nanocomposites

Maintaining the atmospheric CO2 by its utilization in the production of valuable solar fuel like methane is one of the major challenges for humankind. Photocatalytic reduction of CO2 is a vital approach for its consumption by conversion into a valuable chemical product. Here, we prepared In2O3-rGO nanocomposites with varying reduced graphene oxide (rGO) content for the investigation of photocatalytic reduction of CO2. The product yield obtained by photocatalytic reduction of CO2 by visible light source was quantified by exploring the gas chromatography measurements. The catalytic activity of In2O3-rGO nanocomposites towards the photocatalytic reduction process of CO2 to CH4 gets enhanced as compared to In2O3 nanostructures due to the enhancement of lifetime of separation of photogenerated electron-hole pairs, which assist in improvement of charge transfer from In2O3 to rGO under visible light source. The In2O32wt%rGO nanocomposite exhibits a maximum methane yield of 953.72 μmol.g−1. The highest catalytic performance of In2O3-2wt%rGO nanocomposite may be attributed to improvement in its optical properties such as optical band gap and oxygen vacancies (Vo) defects by the addition of rGO in it. A mechanism based on the oxygen vacancies mediated charge transfer process is invoked to explain the observed enhancement in the photocatalytic reduction of CO2.

A novel N-doped graphene oxide enfolded reduced titania for highly stable and selective gas-phase photocatalytic CO2 reduction into CH4: An in-depth study on the interfacial charge transfer mechanism

A desire for renewable alternatives to fossil fuels can be achieved by utilizing CO2, H2O, and solar energy to generate solar fuels. A novel N-doped graphene oxide enfolded reduced titania (NGO-RT) composite was demonstrated for photocatalytic CO2 reduction into CH4. Later, a small amount of Pt NPs was deposited on NGO-RT that increases the catalytic performance towards CH4 formation. The optimized Pt1.0%-NGO-RT catalyst displayed a selective visible-light CO2 reduction into CH4 using a flow reactor system with ≈12 and ≈2 times higher activity than pristine RT and NGO-RT, respectively. The catalyst demonstrated long-term stability over 35 h. The photo-induced CO2 reduction mechanism was first validated through the electron transfer process, where charge trapping by Ti3+ states near the conduction band of RT plays a vital role in the selective CH4 evolution. These trapped electrons transfer from RT to the closely connected interface of N-doped graphene oxide and Pt NPs to restrict the recombination of electron/hole pair. The improved catalytic performance can be attributed to RT’s downward band bending at the NGO-RT interface, where electron transfer from RT to NGO decreases the charge recombination.

HI-Light: A Glass-Waveguide-Based "Shell-and-Tube" Photothermal Reactor Platform for Converting CO2 to Fuels.

SummaryIn this work, we introduce HI-Light, a surface-engineered glass-waveguide-based “shell-and-tube” type photothermal reactor which is both scalable in diameter and length. We examine the effect of temperature, light irradiation, and residence time on its photo-thermocatalytic performance for CO2 hydrogenation to form CO, with a cubic phase defect-laden indium oxide, In2O3-x(OH)y, catalyst. We demonstrate the light enhancement effect under a variety of reaction conditions. Notably, the light-on performance for the cubic nanocrystal photocatalyst exhibits a CO evolution rate at 15.40 mmol gcat−1 hr−1 at 300°C and atmospheric pressure. This is 20 times higher conversion rate per unit catalyst mass per unit time beyond previously reported In2O3-x(OH)y catalyst in the cubic form under comparable operation conditions and more than 5 times higher than that of its rhombohedral polymorph. This result underscores that improvement in photo-thermocatalytic reactor design enables uniform light distribution and better reactant/catalyst mixing, thus significantly improving catalyst utilization.

An unprecedent hydride transfer pathway for selective photocatalytic reduction of CO2 to formic acid on TiO2

Herein we report that hydrogenated TiO2 can act as hydride donor to realize the selective photocatalytic CO2 reduction to formic acid under UV illumination. In situ FT-IR studies indicated that the adsorption modes of CO2 were divergent on Ar-treated and H2-treated TiO2, and consequently, CO was generated on Ar-treated TiO2 whereas the exclusive reduction product on hydrogenated TiO2 was formic acid during the photocatalytic CO2 reduction. EPR and XPS spectroscopy further demonstrated that EPR-active O-vacancy was dominant on Ar-treated sample, while the hydrogenation introduced H on the surface to form EPR-silent hydride-like Ti-H-Ti site. The 2D 1H-13C solid-state NMR experiments corroborated the specific adsorption of CO2 on this H site. Accordingly, the preferential generation of formic acid should originate from the hydride transfer to the adsorbed CO2. Our results first demonstrate that hydrogenation can produce hydride-like sites and enable TiO2 to act as a hydride reagent during the photocatalytic reactions.

Well-Designed 3D/2D/2D WO3/Bt/g-C3N4 Z-Scheme Heterojunction for Tailoring Photocatalytic CO2 Methanation with 2D-Layered Bentonite-Clay as the Electron Moderator under Visible Light

Photocatalytic CO2 reduction to renewable hydrocarbon fuels is a promising strategy to address global energy issues; however, producing fuels like CH4 is highly challenging under visible light. In this work, fabrication of a two-dimensional bentonite (2D-Bt) nanosheet mediated WO3/g-C3N4 Z-scheme heterojunction for highly selective photocatalytic CO2 reduction to CH4 under visible light has been investigated. The photocatalytic performance of the newly developed WO3-embedded 2D pillared Bt with 2D g-C3N4 composite for selective photocatalytic CO2 reduction to methane was studied using H2O as the reducing agent under visible light. WO3/Bt/g-C3N4 (WBCN) exhibits the highest photocatalytic activity for CH4 production, which was 6.01, 6.76, and 25.30 times higher than using WO3/g-C3N4, Bt/g-C3N4, and g-C3N4 samples, respectively. Noticeably, WO3-coupled with g-C3N4 was favorable for CO production; however, introducing Bt layered clay was in favor of methane formation during the CO2 reduction process. Additionally, the Z-scheme of the WO3/g-C3N4 composite with Bt as the electron moderator could promote photoinduced charge separation and redox ability of the separated charge carriers, resulting in excellent CO2 reduction to CH4. The rate of reaction was dependent only on the external mass transfer due to surface reactions over the WBCN composite catalyst. With increasing photon flux, methane production was further enhanced due to the thermodynamically favorable process for the activation of CO2 methanation reaction. Besides, good cycling ability was observed due to the presence of a layered clay structure, which was sustained in multiple cycles without obvious deactivation. This study provides a green clay based noble-metal-free approach to construct a structured composite photocatalyst with a Z-scheme charge carrier and would be beneficial for CO2 reduction and other solar energy applications.

Selective CO2 Photoconversion on Low-Coordinate TiO2

The selective conversion of CO2 into desired hydrocarbon products remains a challenge in photocatalysis. In this issue of Chem, Feng and colleagues report a strong-magnetic-field-assisted strategy for forming active low-coordinate (100) facets on TiO2 nanotubes, enabling selective photoconversion of CO2 into the C2 product C2H5OH under visible light.

Construction of Thiazolo[5,4-d]thiazole-based Two-Dimensional Network for Efficient Photocatalytic CO2 Reduction.

The efficient conversion of CO2 to chemical fuels driven by solar energy is still a challenging research area in photosynthesis, in which the conversion efficiency greatly relies on photocatalytic coenzyme NADH regeneration. Herein, a photocatalyst/biocatalyst synergetic system based on a conjugated microporous polymer (CMP) was prepared for sustainable and highly selective photocatalytic reduction of CO2 to methanol. Two thiazolo[5,4-d]thiazole-linked CMPs (TZTZ-TA and TZTZ-TP) were designed and synthesized as photocatalysts. Slight skeleton modification led to a great difference in their photocatalytic performance. Triazine-based TZTZ-TA exhibited an unprecedentedly high NADH regeneration efficiency of 82.0% yield within 5 min. Furthermore, the in situ photocatalytic NADH regeneration system could integrate with three consecutive enzymes for efficient conversion of CO2 into methanol. This CMP-enzyme hybrid system provides a new avenue for accomplishing the liquid sunshine from CO2.

Fusiform-Shaped g-C3 N4 Capsules with Superior Photocatalytic Activity.

Carbon nitride (g-C3 N4 ) nanostructure rebuilding is an effective means to modify its photocatalytic properties, especially the hollow micron-nanostructure. The increased scattering in the body effectively improves the light utilization efficiency and improves catalytic properties. In this work, fusiform-shaped g-C3 N4 capsules are created by controlling the nucleation kinetics of supramolecular assemblies. The fusiform-shaped capsule micron-nanostructure is synthesized with ultrathin wall thickness and adjusted carbon/nitride ratios which decrease the recombination rate of photo-generated carriers. The hollow nanostructure and relatively higher specific surface area of the fusiform-shaped capsule effectively enhance light scattering inside body and lead to an enhanced carrier utilization efficiency. Moreover, the decrease of bandgap and relatively negative conduction band position affect the response of hollow fusiform-shaped g-C3 N4 capsules (Hf-g-C3 N4 ) in visible light region and improve the photo-reducing performance. In term of H2 evolution property, Hf-g-C3 N4 has been improved to 7052 µmol g-1 h-1 , which is 10.9 times higher compared with bulk structure. More importantly, Hf-g-C3 N4 can produce CH4 at the rate of 1.63 µmol g-1 h-1 without help of co-catalyst and hole sacrificial agent in the photocatalytic reduction reaction of CO2 to CH4 . At same time, the selective photocatalytic reduction of CO2 is another advantage of Hf-g-C3 N4 .

Hierarchically structured semiconductor@noble-metal@MOF for high-performance selective photocatalytic CO2 reduction

Photocatalytic CO2 reduction to convert solar energy to clean energy remains a critical challenge in exploring efficient catalysts. Herein, a hierarchical structured BiVO4@Au@UiO-66-NH2 with high photocatalytic activity was fabricated. The theoretical calculations revealed that the metal–organic framework (MOF) with relative higher conduction band (CB) and UiO-66-NH2 with relative lower valence band (VB) could absorb full light spectrum, combining Au nanoparticle with suitable Fermi level into a particulate tandem heterojunction. This configuration can not only lower the activation barrier of CO2 reduction using the rich active site of MOF, but also improve the selectivity toward CO by optimizing the reaction pathway. Notably, the experimental evaluation proved that BiVO4@Au@UiO-66-NH2 displays a producing rate of 232.7 μmol h−1 g−1 for CO and a selectivity of 97.2%. The investigation reveals that elaborately integrating multiple functional components into such a hierarchical structure enables optimizing crucial processes in photocatalytic CO2 conversion and enhancing selectivity via synergistic catalysis.

Crystalline Carbon Nitride Supported Copper Single Atoms for Photocatalytic CO2 Reduction with Nearly 100% CO Selectivity.

Single metal atom photocatalysts have received widespread attention due to the rational use of metal resources and maximum atom utilization efficiency. In particular, N-rich amorphous g-C3N4 is always used as a support to anchor single metal atoms. However, the enhancement of photocatalytic activity of g-C3N4 by introducing a single atom is limited due to the bulk morphology and the excess defects of amorphous g-C3N4. Here, we report crystalline g-C3N4 nanorod supported copper single atoms by molten salts and the reflux method. The prepared single Cu atoms/crystalline g-C3N4 photocatalyst (Cu-CCN) shows highly selective and efficient photocatalytic reduction of CO2 under the absence of any cocatalyst or sacrificial agent. The introduction of single Cu atoms can be used as the CO2 adsorption site, thus increasing the adsorption capacity of Cu-CCN samples to CO2. Theoretical calculation results show that reducing CO2 to CH4 on Cu-CCN samples is an entropy-increasing process, whereas reducing CO2 to CO is an entropy-decreasing process. As a result, the Cu-CCN samples exhibited enhanced photocatalytic CO2 reduction with nearly 100% selective photocatalytic CO2 to CO conversion. The mechanism of photocatalytic CO2 reduction over Cu-CCN samples was proposed based on in situ Fourier transform infrared spectra, X-ray absorption spectroscopy, and density functional theory calculation. This work provides an in-depth understanding of the design of photocatalysts for enhancing active sites of the reactants.

Selective photocatalytic reduction of CO2 to CO mediated by a [FeFe]-hydrogenase model with a 1,2-phenylene S-to-S bridge

Photocatalytic reduction of CO2 to CO is a promising approach for storing solar energy in chemicals and mitigating the greenhouse effect of CO2. Our recent studies revealed that [(μ-bdt)Fe2(CO)6] (1, bdt = benzene-1,2-dithiolato), a [FeFe]-hydrogenase model with a rigid and conjugate S-to-S bridge, was catalytically active for the selective photochemical reduction of CO2 to CO, while its analogous complex [(μ-edt)Fe2(CO)6] (2, edt = ethane-1,2-dithiolato) was inactive. In this study, it was found that the turnover number of 1 for CO evolution reached 710 for the 1/[Ru(bpy)3]2+/BIH (BIH = 1,3-dimethyl-2-phenyl-2,3-dihydro-1<I>H</I>-benzo[d]-imidazole) system under optimal conditions over 4.5 h of visible-light irradiation, with a turnover frequency of 7.12 min−1 in the first hour, a high selectivity of 97% for CO, and an internal quantum yield of 2.8%. Interestingly, the catalytic selectivity of 1 can be adjusted and even completely switched in a facile manner between the photochemical reductions of CO2 to CO and of protons to H2 simply by adding different amounts of triethanolamine to the catalytic system. The electron transfer in the photocatalytic system was studied by steady-state fluorescence and transient absorption spectroscopy, and a plausible mechanism for the photocatalytic reaction was proposed.

Recycling heavy metals from wastewater for photocatalytic CO2 reduction

Polluted water and exhaust gas released from industrial activities cause a series of environmental issues such as heavy metals accumulation and greenhouse effect. Here, we have proposed an “adsorbent-to-photocatalyst” conversion strategy to bridge water remediation with photocatalytic CO2 reduction. Harmful heavy metals in polluted water are removed and collected by adsorbents, which are converted into valuable photocatalysts for CO2 reduction without secondary treatment. Calcium silicate hydrate (CSH) nanosheets are prepared as an ideal “bridge”. Their ultrathin thickness (2.8 nm), ultrahigh surface area (637.2 m2 g−1), and abundant surface hydroxyls are much favorable for both heavy metals removal and photocatalysis processes. Four typical heavy metals including Cu2+, Zn2+, Ni2+, and Pb2+ are selected for studies. Interestingly enough, in the case of Ni2+ removal, CSH nanosheets undergo phase change and they are spontaneously converted into a new semiconductor nickel silicate hydroxide. The nickel silicate hydroxide has a suitable energy level for reducing CO2 into CO. And its strong CO2 adsorption and abundant exposed Ni2+ sites contribute to efficient and selective photocatalytic CO2 reduction. The CO yield is up to 1.71 × 104 μmol g−1 h−1 with 99.2% selectivity under visible light.

Construction of 2D/2D Bi2Se3/g-C3N4 nanocomposite with High interfacial charge separation and photo-heat conversion efficiency for selective photocatalytic CO2 reduction

Solar-energy-driven CO2 conversion into high-valued fuels has been considered as a promising strategy to alleviate the greenhouse effect and energy crisis problems. However, the rapid charge recombination, poor light utilization and low selectivity, etc. still limit the efficiency of photocatalytic CO2 reduction. In this work, a novel 2D/2D Bi2Se3/g-C3N4 heterojunction composite has been developed to investigate the improved photocatalytic activity towards CO2 reduction selectively. Fortunately, an intimate interaction was formed between 2D Bi2Se3 and 2D g-C3N4, which is very beneficial for the charge separation and transfer. In this composite, Bi2Se3 not only acted as a cocatalyst liked role, but also played as an extra heater for photocatalytic reaction by effective photo-to-heat conversion. As expected, the 2D/2D Bi2Se3/g-C3N4 composite presented much improved photocatalytic ability for CO2 reduction to CO, which is about 6.3 times higher than that of pristine g-C3N4 under the irradiation of full spectrum. Notably, the product from CO2 reduction was nearly 100% CO without other carbon products, and the selectivity for CO was greater than 90% over H2 evolution. The experimental tests and DFT calculations confirmed that the superiority of photocatalytic CO2 reduction ability of Bi2Se3/g-C3N4 composite over other counterparts should be attributed to the synergetic effect of highly improved charge separation and strong photo-to-heat conversion efficiency. Meanwhile, the CO2 reduction process was studied by in-situ FTIR in detail. The as-proposed composite in this work might provide a potential strategy for developing high efficiency of photocatalytic CO2 reduction to valuable fuels.

Structural engineering of 3D hierarchical Cd0.8Zn0.2S for selective photocatalytic CO2 reduction

The solar-driven catalytic conversion of CO2 to useful chemical fuels is regarded as an environmentally friendly approach to reduce the consumption of fossil fuels and mitigate the greenhouse effect. However, it is highly intriguing and challenging to promote the selectivity and efficiency of visible-light-responsive photocatalysts that favor the adsorption of CO2 in photoreduction processes. In this work, three-dimensional hierarchical Cd0.8Zn0.2S flowers (C8Z2S-F) with ultrathin petals were successfully synthesized through an in-situ self-assembly growth process using sodium citrate as a morphology director. The flower-like Cd0.8Zn0.2S solid solution exhibited remarkable photocatalytic performance in the reduction of CO2, generating CO up to 41.4 μmol g−1 under visible-light illumination for 3 h; this was nearly three times greater than that of Cd0.8Zn0.2S nanoparticles (C8Z2S-NP) (14.7 μmol g−1). Particularly, a comparably high selectivity of 89.9% for the conversion of CO2 to CO, with a turnover number of 39.6, was obtained from the solar-driven C8Z2S-F system in the absence of any co-catalyst or sacrificial agent. Terahertz time-domain spectroscopy indicated that the introduction of flower structures enhanced the light-harvesting capacity of C8Z2S-F. The in situ diffuse reflectance infrared Fourier transform spectroscopy unveiled the existence of surface-adsorbed species and the conversion of photoreduction intermediates during the photocatalytic process. Empirical characterizations and predictions of the photocatalytic mechanism demonstrated that the flower-like Cd0.8Zn0.2S solid solution possessed desirable CO2 adsorption properties and an enhanced charge-transfer capability, thus providing a highly effective photocatalytic reduction of CO2.

Selective photocatalytic CO2 reduction over Zn-based layered double hydroxides containing tri or tetravalent metals

Photocatalytic CO2 reduction holds promise as a future technology for the manufacture of fuels and commodity chemicals. However, factors controlling product selectivity remain poorly understood. Herein, we compared the performance of a homologous series of Zn-based layered double hydroxide (ZnM-LDH) photocatalysts for CO2 reduction. By varying the trivalent or tetravalent metal cations in the ZnM-LDH photocatalysts (M = Ti4+, Fe3+, Co3+, Ga3+, Al3+), the product selectivity of the reaction could be precisely controlled. ZnTi-LDH afforded CH4 as the main reduction product; ZnFe-LDH and ZnCo-LDH yielded H2 exclusively from water splitting; whilst ZnGa-LDH and ZnAl-LDH generated CO. In-situ diffuse reflectance infrared measurements, valence band XPS and density function theory calculations were applied to rationalize the CO2 reduction selectivities of the different ZnM-LDH photocatalysts. The analyses revealed that the d-band center (εd) position of the M3+ or M4+ cations controlled the adsorption strength of CO2 and thus the selectivity to carbon-containing products or H2. Cations with d-band centers relatively close to the Fermi level (Ti4+, Ga3+ and Al3+) adsorbed CO2 strongly yielding CH4 or CO, whereas metal cations with d-band centers further from the Fermi level (Fe3+ and Co3+) adsorbed CO2 poorly, thereby yielding H2 only (from water splitting). Our findings clarify the role of trivalent and tetravalent metal cations in LDH photocatalysts for the selective CO2 reduction, paving new ways for the development of improved LDH photocatalyst with high selectivities to specific products.

Photocatalytic CO2 conversion: What can we learn from conventional COx hydrogenation?

Solar-driven reduction of CO2 into fuels/feedstocks is a promising strategy for addressing energy and CO2 emission issues. Despite great research efforts, it still remains a grand challenge to achieve efficient and highly selective reduction of CO2 owing to the large bond energy of CO2 and the diversity of reduction products. In addition to the control of light harvesting and charge transfer like photocatalytic water splitting, the design of catalytically active sites is highly important to promote CO2 reduction activity and selectivity (e.g., C-C coupling). In fact, we can learn a lot from conventional CO2 hydrogenation and syngas conversion in terms of active site design. In this article, we demonstrate how to design catalytically active sites for efficient and highly selective photocatalytic reduction of CO2 by sorting out the rules from the existing research on conventional COx hydrogenation, with a focus on enhancing C[double bond, length as m-dash]O activation and C-C coupling to form value-added products. This article aims to highlight the challenges in the field of photocatalytic CO2 conversion and the connection of photocatalysis with conventional catalytic systems, providing the readers the opportunities to join the research.

Facile synthesis of Mo-doped TiO2 for selective photocatalytic CO2 reduction to methane: Promoted H2O dissociation by Mo doping

Noble-metal co-catalysis could increase the CH4 product selectivity for photocatalytic CO2 reduction by TiO2. However, the high cost and scarcity of noble metals are key obstacles for their extensive use. Thus, it is necessary to explore cheap alternatives. Herein, Mo-doped TiO2 with different Mo concentrations were successfully prepared via a one-pot hydrothermal method at 473 K. The activity measurements of the photocatalysts show that the CH4 selectivity is increased with the Mo concentrations increasing and reaches 54.1 % at a Mo concentration of about 0.3 wt%. With further increasing the Mo concentrations, the CH4 selectivity begins to decrease. Transient photocurrent and fluorescence emission spectroscopy measurements, IR spectra for adsorbed D2O and ·OH trapping suggest that the promoted electron-hole separation and proton supply are together responsible for the enhanced CH4 selectivity. Moreover, photocatalytic CO, formaldehyde, and methanol reductions with H2O and ·CH3 trapping show that the enhanced CH4 selectivity is not directly related with the interaction of CO2 with catalyst surfaces. These reaction results also imply that photocatalytic CO2 reduction might follow the fast-deoxygenation pathway over TiO2-based catalysts. The present work supplies a guide to explore cheap modifiers for selective photocatalytic CO2 reduction to CH4.

In situ no-slot joint integration of half-metallic C(CN)3 cocatalyst into g-C3N4 scaffold: An absolute metal-free in-plane heterosystem for efficient and selective photoconversion of CO2 into CO

An absolute metal-free in-plane heterosystem consisting of g-C3N4 as scaffold and embedded half-metallic C(CN)3 as cocatalysts was conceptually designed for photoconversion of CO2. The no-slot joint between half-metallic C(CN)3 and g-C3N4 through covalent bonding generates a unique two-dimensional, π-conjugated hybrid structure, allowing obstacle-free transferring of the photogenerated electrons in g-C3N4 into C(CN)3 via an intrinsic driving force. Our theoretical calculations together with the in-situ Fourier transform infrared spectra indicate that the most negative charge distribution and binding energy with CO2 for C(CN)3 allow outstanding capture and chemical activation capacity toward CO2, and subsequently enable the optimized heterosystem to exhibit highly efficient and selective photocatalytic reduction of CO2 into CO, 7.8 and 1.9 times those produced with pristine and Pt-modified g-C3N4, respectively. The no-slot joint of organic half-metal cocatalysts with g-C3N4 may open up new opportunities for metal-free, polymer-based photocatalytic systems for CO2 conversion and solar fuel generation.