Advanced sustainable systems 

About: Advanced sustainable systems is an academic journal published by Wiley. The journal publishes majorly in the area(s): Chemistry & Engineering. It has an ISSN identifier of 2366-7486. Over the lifetime, 286 publications have been published receiving 843 citations.

C3N4/PDA S‐Scheme Heterojunction with Enhanced Photocatalytic H2O2 Production Performance and Its Mechanism

Abstract: Developing a high‐performance photocatalyst is important for realizing efficient photocatalytic H2O2 generation. Herein, a novel step‐scheme (S‐scheme) heterojunction photocatalyst C3N4/PDA (CNP) comprised of ultrathin g‐C3N4 (U‐CN) and polydopamine (PDA) is constructed by in situ self‐polymerization. The optimal photocatalyst presents an excellent H2O2 production rate of 3801.25 µmol g−1 h−1 under light irradiation, which is about 2 and 11 times higher than that of pure U‐CN and PDA, respectively, and exceeds most of the reported C3N4‐based photocatalysts. The improvement of photocatalytic activity is ascribed to the synergistic effect of improved light absorption and promoted charge separation and transfer induced by the S‐scheme heterojunction. In situ irradiated X‐ray photoelectron spectroscopy (ISI‐XPS) reveals that the charge transfer route matches the S‐scheme mechanism. Rotating disk electrode (RDE) measurements and electron spin resonance (ESR) spectroscopy verify that H2O2 is produced by a two‐step one‐electron process. This work highlights a promising method to construct high‐performance S‐scheme heterojunction photocatalysts through the hybridization of PDA and C3N4.

Recent Development of Hierarchical Metal Oxides Based Gas Sensors: From Gas Sensing Performance to Applications

Abstract: Gas sensors based on metal oxides have attracted wide attention, due to their inherent advantages such as low cost, small size, fast response, and easy usage. Recently, much effort have been put into the design of metal oxide‐based sensing materials to further improve the performance of gas sensors. Among them, the fabrication of hierarchical metal oxide‐based sensing materials has become the most attractive strategy. In this article, the authors widely review the last decade of development of hierarchical metal oxide‐based gas sensors, in which several representative gases including formaldehyde, acetone, H2S, amines, and water are chosen as the analytes to discuss in depth. The application fields cover indoor air quality monitoring, breath analysis, and food quality and safety. The research advances for each gas is summarized from the perspective of excellent sensing performance in terms of low operating temperature and detection limit, high selectivity, fast responses, and humidity independent responses. Furthermore, the accepted sensing mechanism of metal oxide‐based gas sensors and widely used technology to verify these mechanisms are both included. Finally, the outlook and challenges for future investigations of hierarchical metal oxide‐based gas sensors are also discussed from the perspectives of theory and practice.

A Review on Photothermal Conversion of Solar Energy with Nanomaterials and Nanostructures: From Fundamentals to Applications

Abstract: Solar energy is a green, sustainable, and de facto inexhaustible energy source for mankind. The conversion of solar energy into other forms of energy has attracted extensive research interest due to climate change and the energy crisis. Among all the solar energy conversion technologies, photothermal conversion of solar energy exhibits unique advantages when applied for water purification, desalination, high‐temperature heterogeneous catalysis, anti‐bacterial treatments, and deicing. In this review, the various photothermal conversion mechanisms based on different forms of heat release are summarized and some of the latest examples are presented. In addition, the necessary prerequisites for solar‐driven photothermal materials toward their practical applications are also discussed. Further, the latest advances in photothermal conversion of solar energy are discussed, focusing on different types of photothermal applications. Finally, a summary is given and the challenges and opportunities in the photothermal conversion of solar energy are presented. This review aims to give a comprehensive understanding of emerging solar energy conversion technologies based on the photothermal effect, especially by using nanomaterials and nanostructures.

State‐of‐the‐Art Advances, Development, and Challenges of Metal Oxide Semiconductor Nanomaterials for Photothermal Solar Steam Generation

Abstract: Solar steam generation has drawn high levels of attention from the research community in recent years due to its wide application and abundantly available energy source—sunlight. To the best of the author's knowledge, a specialized overview of photothermal semiconductor solar steam generation has not been conducted to date. In this review, the recently reported solar evaporators using metal oxide semiconductors as the photoabsorber material are investigated, from the perspective of nanostructure, synthesis method, and installation method. A timeline sequence map is generated with the CiteSpace analysis tool to visualize the trend of metal oxide semiconductors as photoabsorbers. The nanostructure of metal oxide semiconductor is emphasized, due to its significant effect on regulating photothermal efficiency in solar steam generation. In addition, other considerations are suggested to enable a fair evaluation of future synthesized photoabsorbers, including cost, stability, reproducibility, recyclability, and regenerative ability. A brief summary of divergent application of solar steam generation is conducted to show the merits of solar steam generation, as well to provide insights for production of photoabsorbers targeted to varying usage and scenarios. Furthermore, the challenges and opportunities of metal oxide solar steam generation system are elaborated from the viewpoint of the authors, with the aim to provide useful insights for future development of photothermal solar steam generation.

Overcoming Electron Transfer Efficiency Bottlenecks for Hydrogen Production in Highly Crystalline Carbon Nitride‐Based Materials

Abstract: The hydrogen evolution reaction (HER) is a complex reaction involving many interdependent physicochemical steps. Highly ordered carbon nitride‐based materials, such as Na‐PHI and K‐PHI, display some of the highest activities for H2 evolution among the carbon nitride‐based materials, due to their electronic properties, but also the presence of cyanimide terminations, which favors the charge transfer for the Pt cocatalyst nanoparticles (NPs). For such highly optimized semiconductor structures, the necessity to control and improve other steps of the photocatalytic process becomes essential, in particular the poor electron transfer from the Pt NPs to the protons in solution over the Helmholtz or Stern layer. Taking highly ordered Na‐PHI as a test material, the influence of water‐dissolved alkali cations on the HER is systematically studied and it is experimentally verified that the electron transfer from the Pt NPs to the protons in solution limits the efficiency of heterogeneous carbon nitride‐based catalysts. This paper explains how hydrated alkali cations influence electron transfer and are able to boost the H2 evolution rate of the same Na‐PHI from 2401 up to 5330 µmol h−1 g−1 with an apparent quantum yield of 13% at 420 nm.