The gradual depletion of fossil fuel reserves that contribute to ~85% of global energy production and release of toxic effluents urges the transformation toward renewable fuels. Thus, the sustainable utilization of sunlight for water splitting and CO2 reduction with heterogeneous photocatalysts has come to light. As a semiconductor photocatalyst, ZnIn2S4 has hit the limelight owing to its narrow bandgap and visible‐light‐responsive properties. However, the limitations of ZnIn2S4 include limited active sites, fast charge‐carrier recombination, and low photoconversion efficiency. Beginning from the fundamental photocatalytic mechanism, this review then provides in‐depth insights into several modification strategies of ZnIn2S4, extending from defect engineering, facet engineering, cocatalyst loading to junction engineering, enabling the synergistic construction of high‐performance ZnIn2S4‐based systems. Subsequently, the structure‐performance relation of ZnIn2S4‐based photocatalysts for hydrogen evolution (HER), overall water splitting (OWS), and CO2 reduction applications in the last 4 years will be discussed and concluded by the future perspectives of this frontier.

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/eom2.12204

Shining light on
 
 ZnIn
 2
 S
 4
 
 photocatalysts: Promotional effects of surface and heterostructure engineering toward artificial photosynthesis

Ultrathin porous graphitic carbon nitride from recrystallized precursor toward significantly enhanced photocatalytic water splitting.

Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon neutrality. Photocatalysis, a process that transforms solar energy into clean fuels through a photocatalyst, represents a felicitous direction toward sustainability. Eco-rich metal-free graphitic carbon nitride (g-C3N4) is profiled as an attractive photocatalyst due to its fascinating properties, including excellent chemical and thermal stability, moderate band gap, visible light-active nature, and ease of fabrication. Nonetheless, the shortcomings of g-C3N4 include fast charge recombination and limited surface-active sites, which adversely affect photocatalytic reactions. Among the modification strategies, point-to-face contact engineering of 2D g-C3N4 with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area, short effective charge-transfer pathways, and quantum confinement effects. This review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g-C3N4 in the construction of point-to-face heterojunction interfaces. Notably, 0D materials such as metals, metal oxides, metal sulfides, metal selenides, metal phosphides, and nonmetals on g-C3N4 with different charge-transfer mechanisms are systematically discussed along with controllable synthesis strategies. The applications of 0D/2D g-C3N4-based photocatalysts are focused on solar-to-energy conversion via the hydrogen evolution reaction, the CO2 reduction reaction, and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction pathways. Finally, future perspectives for developing high-efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes, large-scale production, machine learning integration, and multidisciplinary advances for technological breakthroughs. 

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/cey2.252

Point‐to‐face contact heterojunctions: Interfacial design of 0D nanomaterials on 2D g‐C
 3
 N
 4
 towards photocatalytic energy applications

The functions of interfacial synergy in heterojunction catalysts are diverse and powerful, providing a route to solve many difficulties in energy conversion and organic synthesis. Among heterojunction-based catalysts, the Mott-Schottky catalysts composed of a metal-semiconductor heterojunction with predictable and designable interfacial synergy are rising stars of next-generation catalysts. We review the concept of Mott-Schottky catalysts and discuss their applications in various realms of catalysis. In particular, the design of a Mott-Schottky catalyst provides a feasible strategy to boost energy conversion and chemical synthesis processes, even allowing realization of novel catalytic functions such as enhanced redox activity, Lewis acid-base pairs, and electron donor-acceptor couples for dealing with the current problems in catalysis for energy conversion and storage. This review focuses on the synthesis, assembly, and characterization of Schottky heterojunctions for photocatalysis, electrocatalysis, and organic synthesis. The proposed design principles, including the importance of constructing stable and clean interfaces, tuning work function differences, and preparing exposable interfacial structures for designing electronic interfaces, will provide a reference for the development of all heterojunction-type catalysts, electrodes, energy conversion/storage devices, and even super absorbers, which are currently topics of interest in fields such as electrocatalysis, fuel cells, CO2 reduction, and wastewater treatment.

Design of the Synergistic Rectifying Interfaces in Mott-Schottky Catalysts.

As one of the most attractive technologies, photocatalysis arouses tremendous interest to directly harvest, convert, and store renewable solar energy for solving the energy crisis. Zinc indium sulfide (ZnIn2S4), a novel ternary metal chalcogenide, is highly desired owing to its non‐toxicity, low cost, and easy fabrication. However, it still suffers from some problems, including low charge‐carrier transfer rate and the ultrafast electron–hole recombination. Hence, various efficient modification methods are developed for enhancing the photocatalytic performance of ZnIn2S4 nanomaterials. Herein, the photocatalytic energy applications of ZnIn2S4‐based nanocomposites are systematically summarized, followed by a thorough discussion on the synthesis methods of ZnIn2S4 micro/nanostructures. Furthermore, special attention is paid to various design strategies, including dimensionality tuning, element doping, vacancy control, cocatalyst loading, and heterojunction construction. Many important energy conversion applications are also addressed, such as photocatalytic water splitting, carbon dioxide reduction, and nitrogen fixation. The influence of physicochemical properties, including structure, optical, electronic, and adsorption, on the charge dynamics for boosted photocatalytic energy applications are concluded to unravel the property–application relationship. Through reviewing the significant state‐of‐the‐art advances on this topic, the current challenges and the crucial issues of ZnIn2S4‐based photocatalysts are prospected.

ZnIn2S4‐Based Nanostructures in Artificial Photosynthesis: Insights into Photocatalytic Reduction toward Sustainable Energy Production

Sparked by natural photosynthesis, solar photocatalysis using metal‐free graphitic carbon nitride (g‐C3N4) with appealing electronic structure has turned up as the most captivating technique to the quest for sustainable energy generation and pollution‐free environment. Nonetheless, low‐dimensional g‐C3N4 is thwarted from sluggish kinetics and rapid recombination of photogenerated carriers upon light irradiation. Among multifarious modification strategies, engineering 2D cocatalysts is anticipated to accelerate redox kinetics, augment active sites and ameliorate electron–hole separation of 2D g‐C3N4 for boosted activity thanks to its face‐to‐face contact surface. It is of timely and technological significance to review the 2D/2D interfaces with state‐of‐the‐art 2D cocatalysts, spanning from carbon‐containing to phosphorus‐containing, metal dichalcogenide, and other cocatalysts. Fundamental principles for each photocatalytic application will be introduced. Thereafter, the recent advances of 2D/2D cocatalyst‐mediated g‐C3N4 systems will be critically evaluated based on their interfacial engineering, emerging roles, and impacts toward stability and catalytic efficiency. Importantly, mechanistic insights into the charge dynamics and structure–performance relationship will be deciphered. Last, noteworthy research directions are prospected to deliver insightful ideas for future development of g‐C3N4. Overall, this review is anticipated to serve as a scaffold and cornerstone in designing dimensionality‐dependent 2D cocatalyst‐assisted g‐C3N4 toward renewable energy and ecologically green environment.

Tailor‐Engineered 2D Cocatalysts: Harnessing Electron–Hole Redox Center of 2D g‐C3N4 Photocatalysts toward Solar‐to‐Chemical Conversion and Environmental Purification

Evolutionary face-to-face 2D/2D bismuth-based heterojunction: The quest for sustainable photocatalytic applications

2D Cocatalysts With the booming interest towards the utilization of solar energy for renewable energy, in article number 2111875, Wee-Jun Ong and co-workers review the recent progress and prospects on 2D/2D cocatalyst/g-C3N4 photocatalysts for solar-to-chemical conversion and environmental purification. Interfacing 2D/2D heterojunctions has been touted as an effective strategy to harness electron-hole redox centers that will prolong the lifetime of photocatalysts and improve the overall performance in energy and environmental science. 

Tailor‐Engineered 2D Cocatalysts: Harnessing Electron–Hole Redox Center of 2D g‐C
 3
 N
 4
 Photocatalysts toward Solar‐to‐Chemical Conversion and Environmental Purification (Adv. Funct. Mater. 29/2022)

Direct conversion of waste CO2 into CH3OH by solar irradiation has emerged as the most enthralling alternative to conventional steam methane reforming, which reduced the concentration of greenhouse gases and the consumption of fossil resources. A cradle-to-gate life cycle assessment was carried out to assess the environmental feasibility of implementing the current g-C3N4-based photocatalytic CO2 reduction system based on 1 kg CH3OH production. It was observed that the emerging photocatalytic CH3OH system induced 68 and 53% less carbon footprint and fossil usage, respectively, in producing the same amount of CH3OH as compared to the conventional approach. The CO2 reduction reaction step was identified as the main contributor in photocatalytic system, which accounted for more than 50% of the total environmental impact scores. In the conventional system, the score points of global warming and fossil depletion contributed the most by the product purification and desulfurization step, respectively. In addition, sensitivity analysis manifested that the lowest environmental burden of 46.50 kg of CO2 equiv carbon emission and 15.27 kg oil equiv fossil consumption was obtained in the photocatalytic CH3OH system upon replacing fossil-based energy with hydro-powered electricity. These results suggest a potent replacement of the incumbent industry system for the amelioration of climate benefits and resource conservation with the advanced development of the photocatalytic system. 

Transition into Net-Zero Carbon Community from Fossil Fuels: Life Cycle Assessment of Light-Driven CO2 Conversion to Methanol Using Graphitic Carbon Nitride

Grayson Zhi Sheng Ling

Papers

Tailor‐Engineered 2D Cocatalysts: Harnessing Electron–Hole Redox Center of 2D g‐C3N4 Photocatalysts toward Solar‐to‐Chemical Conversion and Environmental Purification

Evolutionary face-to-face 2D/2D bismuth-based heterojunction: The quest for sustainable photocatalytic applications

Tailor‐Engineered 2D Cocatalysts: Harnessing Electron–Hole Redox Center of 2D g‐C 3 N 4 Photocatalysts toward Solar‐to‐Chemical Conversion and Environmental Purification (Adv. Funct. Mater. 29/2022)

Transition into Net-Zero Carbon Community from Fossil Fuels: Life Cycle Assessment of Light-Driven CO2 Conversion to Methanol Using Graphitic Carbon Nitride

g-C3N4 photocatalysts: Utilizing electron-hole pairs for boosted redox capability in water splitting