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The wide visible‐light‐driven CO2 reduction to acquire solar fuels is a highly desired green route. Herein, novel ultrathin copper phthalocyanine (CuPc)/α‐Fe2O3 heterojunctions as efficient wide visible‐light‐driven photocatalysts for CO2 reduction are controllably synthesized by the hydroxyl‐induced self‐assembly of CuPc onto ultrathin α‐Fe2O3 as‐pre‐prepared through an Al3+‐regulated hydrothermal method. The optimized CuPc/Fe2O3 heterojunction exhibits about 15‐fold high photoactivity for reducing CO2 to CO and CH4 compared with reported Fe2O3 nanoparticles. The exceptional photoactivity is mainly attributed to the enhanced S‐scheme charge transfer and separation in the resulting closely contacted heterojunction, the extended visible‐light range from molecularly disperse CuPc, and its provided central metal cation (Cu2+) with favorable catalytic function for CO2 activation, mainly by means of the dual‐wavelength photocurrent action spectra, the electrochemical reduction tests, and the in situ diffuse reflectance infrared Fourier transform spectra (DRIFTS). This investigation provides new insight about designing and constructing novel metal phthalocyanine (MPc)‐involved S‐scheme heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2 Z-scheme heterojunction was prepared via coupling Fe-C 3 N 4 and partially oxidized MXenes-derived C-TiO 2 /Ti 3 C 2. It presented excellent catalytic activity and photothermal performance in photo-Fenton reaction toward tetracycline degradation. [Display omitted] Photo-Fenton reaction combining the photocatalytic reaction and Fenton reaction showed excellent degradation performance. However, it highly demanded the catalysts to display outstanding activity in these two reactions. Herein, Fe-doped carbon nitride/MXenes-derived C-TiO 2 /Ti 3 C 2 (Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2) was prepared via two steps: Fe-C 3 N 4 and Ti 3 C 2 were assembled via face-to-face attachment, following by in-situ partial oxidation of Ti 3 C 2 to C-TiO 2. DFT predicted a Z-scheme charge transfer routine via metallic Ti 3 C 2 as bridge, which was verified by EPR and radical trapping experiments. Additionally, PDOS calculation revealed the charge density around the doped-Fe atoms was remarkably increased, leading to better H 2 O 2 activation, which was experimentally confirmed by high yield of •OH. Moreover, Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2 possessed the high photothermal effect to accelerate the surface reaction. By taking advantage of these merits, the degradation rate of Fe-C 3 N 4 /Ti 3 C 2 /C-TiO 2 was at least 4.2 times higher than the reference catalysts. Our work provided an insight toward the g -C 3 N 4 /TiO 2 -based photo-Fenton catalysts with high performance. [ABSTRACT FROM AUTHOR]

In this paper, type-I C 3 N 4 -based isotype heterojunction was prepared. In photocatalyisis-self-Fenton reaction, it displayed high H 2 O 2 yield, outstanding utilization efficiency, and excellent degradation performance. The finding was beneficial to simultaneously solve two problems in traditional Fenton reaction: the source of H 2 O 2 and low utilization efficiency. [Display omitted] Herein, a type-I phosphorus-doped carbon nitride/oxygen-doped carbon nitride (P-C 3 N 4 /O-C 3 N 4) heterojunction was designed for photocatalysis-self-Fenton reaction (photocatalytic H 2 O 2 production and following Fenton reaction). In P-C 3 N 4 /O-C 3 N 4 , the photoinduced charge carriers were effectively separated with the help of internal-electric-field near the interface, ensuring the high catalytic performance. As a result, the production rate of H 2 O 2 in an air-saturated solution was 179 μM·h−1, about 7.2, 2.5, 2.5 and 2.1 times quicker than that on C 3 N 4 , P-C 3 N 4 , O-C 3 N 4 , and phosphorus and oxygen co -doped C 3 N 4 , respectively. By taking advantage of the cascade mode in photocatalysis-self-Fenton reaction, H 2 O 2 utilization efficiency was remarkably improved to 77.7%, about 9.0 times higher than that of traditional homogeneous Fenton reaction. Befitting from the superior yield and utilization efficiency, the degradation performance of P-C 3 N 4 /O-C 3 N 4 was undoubtedly superior than other photocatalysts. This work well addressed two bottlenecks in traditional Fenton reaction: source of H 2 O 2 and their low utilization efficiency, and the findings were beneficial to understand the mechanism and advantage of the photocatalysis-self-Fenton system in environmental remediation. [ABSTRACT FROM AUTHOR]

Phosphorus-doped carbon nitride/phosphorus and sulphur co -doped carbon nitride isotype heterojunction was prepared by a two-step calcination method. They displayed high photoactivity and reusability toward the rhodamine B degradation. Photocatalysis was one of the most promising techniques for environmental remediation. Exploring photocatalysts with high efficiency, low cost and easy preparation was still an ongoing issue. In this work, phosphorus-doped carbon nitride/phosphorus and sulfur co -doped carbon nitride (P-C 3 N 4 /PS-C 3 N 4) isotype heterojunction was prepared by a two-step calcination method. The composite displayed a sheet-like structure with a surface area of 23 m2/g. Compared with pure C 3 N 4 , band gaps of P-C 3 N 4 and PS-C 3 N 4 were only slightly modified during the heteroatom-doping process. Therefore, a well-matched band alignment was constructed, which not only improved the separation efficiency of photogenerated electron-hole pairs, but also well preserved the high oxidizability of holes on valance band and good reducibility of electrons on conduction band. Because of the similarity in physicochemical properties, the interface resistance between P-C 3 N 4 and PS-C 3 N 4 was low, which accelerated the electron transfer and prolonged the lifetime of charge carriers. Although the visible-light utilization was somewhat low in comparison with P-C 3 N 4 and PS-C 3 N 4 , by taking advantage of above merits, P-C 3 N 4 /PS-C 3 N 4 displayed the high photocatalytic activity in rhodamine B degradation, and the reaction rate constant was 0.183 min−1, about 8.7 and 4.0 times higher than those of P-C 3 N 4 and PS-C 3 N 4. Besides high catalytic activity, isotype heterojunction displayed good recyclability, since 95.3% of catalytic activity was maintained after the 5th cycle. The method presented here was facile, economic and environmentally benign, thus it was highly attractive for the application in environmental remediation. [ABSTRACT FROM AUTHOR]

At present, nitrogen-rich graphitic carbon nitride (g -C 3 N 5) has emerged as an alternative for traditional graphitic carbon nitride (g -C 3 N 4), due to better visible-light utilization efficiency and abundant surface functional groups. In this paper, a g -C 3 N 5 /MXenes (Ti 3 C 2) binary heterojunction was prepared and used as a photocatalyst in environmental remediation. In tetracycline (TC) degradation, g -C 3 N 5 /Ti 3 C 2 displayed better performance than those of the reference photocatalysts, including g -C 3 N 5 , g -C 3 N 4 , Ti 3 C 2 and g -C 3 N 4 /Ti 3 C 2. The underlying electron (e -) transfer mechanism was investigated in detail. Besides higher visible-light harvest, better separation efficiency of photo-induced charge carrier and lower surface resistance, an internal-electric-field was established at the interface between g -C 3 N 5 and Ti 3 C 2 , and the driving force for e - transfer was 93.9 mV. hole (h +), 1O 2 , •OH and •O 2 - were involved into TC degradation, where h + played a dominating role due to the high e - transfer efficiency. Benefiting from the good photothermal effect, g -C 3 N 5 /Ti 3 C 2 could efficiently transfer solar energy to thermal energy, leading to the high temperature of catalyst surface and acceleration of the surface degradation reaction rate. This work provided a possibility to construct a g -C 3 N 5 -based visible-light photocatalyst to efficiently degrade the persistent organic contaminants. [Display omitted] • Ti 3 C 2 served as a reservoir for e - transfer from the conduction band of g -C 3 N 5. • Degradation rate of g -C 3 N 5 /Ti 3 C 2 is 2.5 times higher than that of g -C 3 N 4 /Ti 3 C 2. • Internal-electric-field is formed, and the driving force for e - transfer is 93.9 mV. • h +, 1O 2 , •OH and •O 2 - are involved into degradation, the contribution of h + is 82.8%. • g -C 3 N 5 /Ti 3 C 2 shows a better photothermal effect than g -C 3 N 4 /Ti 3 C 2 and g -C 3 N 5. [ABSTRACT FROM AUTHOR]

FeS 2 /MoS 2 @C nanoreactor with FeS 2 /MoS 2 Z-scheme heterojunctions encapsulated inside the carbon shell was prepared as a catalyst in photo-Fenton reaction. [Display omitted] • FeS 2 /MoS 2 @C nanoreactor was prepared by 3 steps: ions exchange, CCIP and calcination. • k value was 9.4 × 10−2 min−1, better than reference catalysts due to confinement effect. • light harvest, photothermal effect, self-produced O 2 yield are higher in nanoreactor. • Contributions follow the order: •OH > h+ >1O 2 >•O 2 –, and their sources are traced. • Complex catalytic mechanism and structure–function relationship are well illustrated. Catalytic reaction confined in the nanoreactor could be accelerated by taking advantage of confinement effect. Photo-Fenton reaction has already been verified as an effective technique for pollutant degradation. Therefore, it was rational to infer that the degradation performance of photo-Fenton reaction inside the nanoreactor could be further improved. Nevertheless, how to construct a suitable nanoreactor to realize the aim was still a challenge. Herein, FeS 2 /MoS 2 @C nanoreactor with FeS 2 /MoS 2 heterojunctions encapsulated inside the carbon capsule was prepared using Fe-MIL-101 as hard template via ions exchange, chelation competition induced polymerization, and calcination in sequence. In photo-Fenton reaction, photo-induced e − followed a Z-scheme transfer path, leading to the well-preserved redox capacity of separated e − and h +. A large amount of reactive species were generated inside the capsule, and their contributions followed the order: •OH > h+ >1O 2 >•O 2 –. The complex catalytic mechanism was disclosed via tracing the source of reactive species. Furthermore, to better illustrate the confinement effect, the broken-FeS 2 /MoS 2 @C was prepared as a reference. The accelerated degradation rate, better visible-light harvest, enhanced photothermal effect, and higher yield of self-produced O 2 inside the integrated capsule were disclosed. This work illustrates the advantage of nanoreactor, and provides a new vision to improve the degradation performance in photo-Fenton reaction. [ABSTRACT FROM AUTHOR]

• Internal-electric-field is built at interface, resulting in a Z-scheme routine of e -. • TC is degraded within 40 min, and k of photo-Fenton reaction is 4.5 × 10−2min−1. • k of photo-Fenton reaction is higher than sum of Fenton reaction and photocatalysis. • Contribution of radicals in TC removal follows the order: •OH surf >•O 2 ->1O 2 > h +>•OH free. • 93.6% of the degradation efficiency of the 1st cycle is maintained after 5 cycles. A Z-scheme heterojunction with sandwich-like structure was prepared. It displayed high degradation efficiency and magnetic recyclability in photo-Fenton reaction, and the catalytic mechanism was carefully investigated. [Display omitted] Herein, the sandwich-like Fe 3 O 4 @FeS 2 @C@MoS 2 composite was prepared via coating MoS 2 shell on the surface of core/shell Fe 3 O 4 @C composite. During the coating process, Fe 3 O 4 was partly sulfurized to FeS 2 , whose energy band was well-matched with that of MoS 2 for a Z-scheme heterojunction. The residual Fe 3 O 4 ensured the rapid separation of heterojunction by magnet. In photo-Fenton reaction, 81.5% of tetracycline was degraded within 40 min, which was higher than the sum of degradation efficiency of Fenton reaction and photocatalytic reaction. 93.6% of the degradation efficiency in the 1st cycle was still maintained after 5 cycles. In mechanism study, the sources of •OH, •O 2 -, 1O 2 and h + were carefully traced, and the contributions of these radicals followed the order: •OH surf >•O 2 ->1O 2 > h +>•OH free. An inner electric field was built at the interface by analyzing the energy band and work functions, which driven the charge carriers transfer followed a Z-scheme path. The findings in this manuscript were beneficial for designing catalysts with high photo-Fenton activity. [ABSTRACT FROM AUTHOR]