Search

The fast recombination of photogenerated electrons and holes remains a major issue in hindering photocatalytic efficiency. Apart from traditional methods, such as rare metal deposition and element doping, the introduction of a built‐in electric field has been proven an efficient way in recent years. Ferroelectrics, which possess spontaneous polarization and associated polarization electric fields, are attracting more attention as photocatalysts. In this study, Bi2MoO6 spheres with different hierarchical upper nanostructures are synthesized through a one‐pot hydrothermal method. With this porous structure and the intrinsic ferroelectricity, BMO spheres present excellent physisorption and photodegradation ability toward dye molecules. After corona poling treatment, the ferroelectric field of the BMO samples was enhanced, and the recombination of charges was suppressed, leading to an obvious increase in photocatalytic rate. The origin BMO‐5 can reach a total degradation of RhB in 20 min, and the polarized BMO‐5 (BMO‐5P) can remove all RhB molecules instantly through the physisorption process. Apart from BMO‐5, other samples also present excellent catalytic behavior. Origin BMO‐2 can fully degrade the RhB in 40 min, and the degradation time of polarized BMO‐2P is 30 min. The hierarchical structure and internal polarized electric field endow BMO spheres with outstanding adsorption purification and photodegradation ability and provide a new comprehensive strategy for the catalyst design. [ABSTRACT FROM AUTHOR]

S‐scheme heterojunction has emerging as a new star in the field of photocatalysis, attributing to its superior separation of photogenerated charge carriers and strong redox abilities. The general designing criteria and several types of S‐scheme heterojunction were provided. Advanced characterization techniques, including Kelvin probe force microscopy, electron paramagnetic resonance spectroscopy, and in‐situ irradiated X‐ray photoelectron spectroscopy, were presented for disclosing the transfer mechanism in S‐scheme heterojunctions. The recent innovations in the application of photocatalytic oxygen reduction reaction in S‐scheme heterojunction based polymeric carbon nitride photocatalyst were discussed. To conclude, this concept highlights the role of S‐scheme heterojunction in photocatalysis and gives future perspectives on their further applications. [ABSTRACT FROM AUTHOR]

Heterojunction TiO2 has attracted great attention in photocatalytic applications due to its high efficiency in the separation of photogenerated electron‐hole pairs and strong ability of light absorption. This work concisely summarizes the distinct crystal phases of TiO2 and elucidates the prevalent methods employed in the synthesis of TiO2 heterojunctions. Furthermore, the review highlights novel strategies for the realization of TiO2 phase transformation, thereby contributing to a deeper understanding and advancement in the application of mixed‐phase TiO2 photocatalysts. [ABSTRACT FROM AUTHOR]

Solar water oxidation is a critical step in artificial photosynthesis. Successful completion of the process requires four holes and releases four protons. It depends on the consecutive accumulation of charges at the active site. While recent research has shown an obvious dependence of the reaction kinetics on the hole concentrations on the surface of heterogeneous (photo)electrodes, little is known about how the catalyst density impacts the reaction rate. Using atomically dispersed Ir catalysts on hematite, we report a study on how the interplay between the catalyst density and the surface hole concentration influences the reaction kinetics. At low photon flux, where surface hole concentrations are low, faster charge transfer was observed on photoelectrodes with low catalyst density compared to high catalyst density; at high photon flux and high applied potentials, where surface hole concentrations are moderate or high, slower surface charge recombination was afforded by low‐density catalysts. The results support that charge transfer between the light absorber and the catalyst is reversible; they reveal the unexpected benefits of low‐density catalyst loading in facilitating forward charge transfer for desired chemical reactions. It is implied that for practical solar water splitting devices, a suitable catalyst loading is important for maximized performance. [ABSTRACT FROM AUTHOR]

Single‐atom (SA) cocatalysis has obvious superiority in promoting solar‐to‐chemical energy conversion. However, easy aggregation of SAs is very unfavorable to its catalysis for high surface energy. Herein, a photoreduction procedure is adopted to immobilize Ni SAs on CdS nanoparticles (NPs) to construct the synergistic electric metal–semiconductor interaction (EMSI) for highly promoting the simulated sunlight‐driven H2O‐to‐H2 (HTH) conversion in alkaline condition (pH = 14.0) without any sacrificial agent addition, and the nanocatalyst with 1.25‰ of Ni carrying capacity (CdS–Ni1.25‰) achieves the highest HTH conversion rate (8149.71 μmol h−1 g−1, 13.0‐fold greater of that of CdS NPs) and stable photostability accompanied by 27.60% of apparent quantum yield (AQY400 nm). Characterizations and density functional theory calculations indicate that the EMSI on CdS–Ni1.25‰ nanocatalyst greatly improves the light absorption capacity and promotes the orderly bulk‐to‐surface migration of photoexcitons, effectively suppressing their recombination kinetics for higher photoexciton utilization efficiency. Under alkaline conditions, high concentration of OH− ions is easy to react with photogenerated holes to generate hydroxyl radicals for effectively inhibiting the oxidation half‐reaction and obtaining higher HTH conversion performance due to significantly reduced energy barriers on atomic Ni sites. This study provides an insight for improving the performance of a conventional photocatalyst through non‐noble metallic SAs cocatalysis. [ABSTRACT FROM AUTHOR]

Organic semiconductor nanoparticles (NPs) are attractive photocatalysts to produce hydrogen from water splitting. Herein, a ternary strategy of incorporating crystalline n‐type molecule IDMIC‐4F into the host system made of p‐type polymer PM6 and n‐type molecule ITCC‐M is demonstrated. ITCC‐M and IDMIC‐4F form compact alloy‐like composite with shorter lattice spacing in the ternary p/n heterojunction NPs, resulting in enhanced exciton dissociation and charge transfer characteristics. As the result, an unprecedented hydrogen evolution rate (HER) of 307 mmol h−1 g−1 and a maximum apparent quantum efficiency of 5.9% at 600 nm are achieved in the optimized ternary NPs (PM6:ITCC‐M:IDMIC‐4F = 1:1.3:0.2), which is among the highest HER from organic photocatalysts to the best of the authors' knowledge. The alloy‐like composite also improves the operational stability of ternary NP photocatalysts. This study shows that synergizing two compatible n‐type small molecules to form alloy‐like composite is a promising approach to design novel organic photocatalysts for boosting the photocatalytic hydrogen evolution efficiency. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Photocatalytic CO2 reduction to fuels and chemicals has been considered as the promising avenue to realize carbon resource recycling. Covalent organic frameworks (COFs) with pre‐designed and tailorable structures are promising platforms for studying the influence of the microenvironment of catalysts on photocatalytic CO2 reduction. Herein, we report three isomorphic COFs (TPHH‐COF, TPPD‐COF and TPBD‐COF) as heterogeneous photocatalysts for CO2 reduction and investigate the different levels of conjugation and planarity of COFs effect on the catalytic activity. Photoelectrochemical measurements show that TPPD‐COF has a narrower band gap and faster photocurrent response compared to TPHH‐COF and TPBD‐COF, probably due to the moderate conjugation and planarity. As the photocatalyst, TPPD‐COF showed the most outstanding photocatalytic activity with the production rates of 951 and 157 μmol·g–1·h–1 for CO and H2, respectively. This study illustrates the close relation between microenvironment and photocatalytic activity and provides new insights for designing high‐performance photocatalysts. [ABSTRACT FROM AUTHOR]

Methane (CH4) is a potent greenhouse gas and the second highest contributor to global warming. CH4 emissions are still growing at an alarmingly high pace. To limit global warming to 1.5 °C, one of the most effective strategies is to reduce rapidly the CH4 emissions by developing large‐scale methane removal methods. The purpose of this perspective paper is threefold. (1) To highlight the technology gap dealing with low concentration CH4 (at many emission sources and in the atmosphere). (2) To analyze the challenges and prospects of solar‐driven gas phase advanced oxidation processes for CH4 removal. And (3) to propose some ideas, which may help to develop solar‐driven gas phase advanced oxidation processes and make them deployable at a climate significant scale. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The development of conjugated polymer photocatalysts for efficient solar‐to‐hydrogen energy conversion is highly desirable for the sustainability of our society. Although the construction of donor‐acceptor (D‐A) structure in conjugated polymer photocatalysts for solar‐to‐hydrogen energy conversion has been well documented, less attention has been paid on how large D and how large A units combined together could achieve the best performance. Herein, a series of D‐A copolymers P(BDT‐DBTSOx) (x = 7, 19, 39, and 79) composed of a benzodithiophene (BDT) donor unit and an oligomeric dibenzo[b,d]thiophene sulfone (DBTSO) acceptor segment were synthesized and studied. It was found that the polymer photocatalytic stabilities under full‐arc irradiation improved upon shortening the length of the acceptor segment. Under visible light irradiation and in the presence of 3 wt% Pt cocatalyst, P(BDT‐DBTSO79) displayed the best performance with an optimal hydrogen evolution rate of 119.3 ± 5.8 mmol·g–1·h–1. This is 1.4‐fold as that of DBTSO homopolymer and 22.5‐fold as that of BDT/DBTSO alternative copolymer, highlighting the importance of acceptor length in D‐A structure for achieving high photocatalytic performance. [ABSTRACT FROM AUTHOR]

Subjected to the manufacturing methods (sputtering or mechanochemical synthesis), the reported high entropy nitrides (HENs) were limited to the forms of coating and powder. Here, we report a novel strategy in preparing HEN ceramic nanofibers (HENCNFs) from liquid precursor via electrospinning followed by high‐temperature NH3 atmosphere nitridation. The as‐prepared HENCNFs include five uniform dispersed metal elements, Ti, Hf, Nb, Ta, and Mo, and have a single face‐centered cubic structure. Interestingly, the obtained HENCNFs show photocatalyst activity in CO2 reduction. The product selectivity of photocatalytic CO2 reduction reaction is 96.4%, and no performance degradation was detected during five cycles photocatalysis test. [ABSTRACT FROM AUTHOR]

The marriage of catalyst nanoparticles and mesoporous supports brings exciting new opportunities in the field of catalysis, which provides the ability to create advanced nanoporous catalysts for a wide range of catalytic processes. It has been found that not only the features of mesoporous supports, such as, surface areas, mesostructures, and pore sizes, are critical for the catalytic performances, but also the unique properties of catalyst nanoparticles, including dispersion, particle size, and loading amount, play critical roles in determining catalytic performance. Those aspects have been discussed partly in previous reviews, but a comprehensive overview on the basic design principles and synthetic methods for the marriage of catalyst nanoparticles and mesoporous supports is still lacking. In this review, the recent progresses in the fabrication of advanced catalysts by incorporation of catalyst nanoparticles into mesoporous supports are summarized. First, the synthetic strategies for the controllable synthesis are reviewed. At the same time, the corresponding chemical‐/physically properties of the resultant supported mesoporous catalysts are highlighted. After that, the catalytic performances of the resultant mesoporous catalysts in the thermal catalysis, photocatalysis, and electrocatalysis are discussed. Moreover, the research challenges and perspectives in this field are assessed. [ABSTRACT FROM AUTHOR]

Frontispiece: Solar Driven Gas Phase Advanced Oxidation Processes for Methane Removal - Challenges and Perspectives Keywords: advanced oxidation process; chlorine; methane oxidation; ozone; photocatalysis; photoreactor EN advanced oxidation process chlorine methane oxidation ozone photocatalysis photoreactor 1 1 1 11/21/22 20221116 NES 221116 Methane (CH SB 4 sb ) is a potent greenhouse gas. Advanced oxidation process, chlorine, methane oxidation, ozone, photocatalysis, photoreactor. [Extracted from the article]