Temperature and pH dual-stimuli-responsive phase-change microcapsules for multipurpose applications in smart drug delivery.

Abstract When it comes to using solar energy to promote catalytic reactions, photocatalysis technology is the first choice. However, sunlight can not only be directly converted into chemical energy through a photocatalytic process, it can also be converted through different energy‐transfer pathways. Using sunlight as the energy source, photocatalytic reactions can proceed independently, and can also be coupled with other catalytic technologies to enhance the overall catalytic efficiency. Therefore, sunlight‐driven catalytic reactions are diverse, and need to be given a specific definition. We propose a timely perspective for catalytic reactions driven by sunlight and give them a specific definition, namely “solar energy catalysis”. The concept of different types of solar energy catalysis, such as photocatalysis, photothermal catalysis, solar cell powered electrocatalysis, and pyroelectric catalysis, are highlighted. Finally, their limitations and future research directions are discussed.

Solar Energy Catalysis

Rational design hybrid nanostructure photocatalysts with efficient charge separation and transfer, and good solar light harvesting ability have critical significance for achieving high solar‐to‐chemical conversion efficiency. Here a highly active and stable composite photocatalyst is reported by integrating ultrathin ZnIn2S4 nanosheets on surface of hollow CdS cube to form the cube‐in‐cube structure. Experimental results combined with density functional theory calculations confirm that the Z‐scheme ZnIn2S4/CdS heterojunction is formed, which highly boosts the charge separation and transfer under the local‐electric‐field at semiconductor/semiconductor interface, and thus prolongs their lifetimes. Moreover, such a structure affords the highly enhanced light‐harvesting property. The optimized ZnIn2S4/CdS nanohybrids exhibit superior H2 generation rate under visible‐light irradiation (λ ≥ 420 nm) with excellent photochemical stability during 20 h continuous operation.

Constructing Direct Z‐Scheme Heterostructure by Enwrapping ZnIn2S4 on CdS Hollow Cube for Efficient Photocatalytic H2 Generation

Artificial photoreduction of CO2 is confined by low separation efficiency of photoinduced charge carriers and poor activation of CO2 over photocatalysts. Herein, a brilliant ultrathin 2D/2D Ni-doped CsPbBr3/Bi3O4Br Z-scheme heterostructure was rationally constructed, which showed superior CO yield of 387.57 μmol g−1 with 98.2% selectivity, 12.3 times higher than that of pristine CsPbBr3. Both experimental results and theoretical calculations confirmed that Ni doping in CsPbBr3 not only efficiently expand spectral response but also is beneficial for the adsorption and activation of CO2. Moreover, in-situ irradiated XPS validated the Z-scheme charge transfer path, forming an internal electric field (IEF) directing from Ni-doped CsPbBr3 to Bi3O4Br, which results in higher charge separation efficiency. Besides, in-situ DRIFTS and DFT studies reveal that the photocatalyst depressed the formation energy of COOH* and CO* . This work shows a new path for boosting photocatalytic CO2 reduction of photocatalysts by the synergistic effect between doping and heterostructure. 

Efficient photocatalytic CO2 conversion over 2D/2D Ni-doped CsPbBr3/Bi3O4Br Z-scheme heterojunction: Critical role of Ni doping, boosted charge separation and mechanism study

Ammonia and nitrates are the most fundamental and significant raw ingredients in human society. Till now, industrial synthetic ammonia by Haber–Bosch process and industrial synthetic nitrates by the Ostwald process have encountered increasingly serious challenges, i.e., high energy consumption, high cost, and environment‐harmful gas emissions. Therefore, developing alternative approaches to achieve nitrogen fixation to overcome the inherent deficiencies of the well‐established Haber–Bosch and Ostwald processes has fascinated scientists for many years, especially the simultaneous formation of ammonia and nitrate directly from N2 molecules, which has been rarely studied. Herein, a heterojunction‐based photocatalytic system is designed to successfully achieve “overall nitrogen fixation,” a sustainable and simultaneous conversion of N2 molecules into ammonia and nitrate products under mild conditions. In this heterojunction, interfacial charge redistribution (ICR) promotes selective accumulations of photogenerated electrons and holes in the CdS and WO3 components. As a result, N2 molecules can be activated and reduced to ammonia products with yields of 35.8 µmol h−1 g−1 by a multi‐electron process, and synchronously oxidized into nitrate products with yields of 14.2 µmol h−1 g−1 by a hole‐induced oxidation coupling process. This work provides a novel insight and promising approach to realize artificial nitrogen fixation under mild condition.

Designing a Redox Heterojunction for Photocatalytic “Overall Nitrogen Fixation” under Mild Conditions

Photocatalytic water splitting is considered one of the most important and appealing approaches for the production of green H2 to address the global energy demand. The utmost possible form of artificial photosynthesis is a two-step photoexcitation known as "Z-scheme", which mimics the natural photosystem. This process solely relies on the effective coupling and suitable band positions of semiconductors (SCs) and redox mediators for the purpose to catalyze the surface chemical reactions and significantly deter the backward reaction. In recent years, the Z-scheme strategies and their key role have been studied progressively through experimental approaches. In addition, theoretical studies based on density functional theory have provided detailed insight into the mechanistic aspects of some breathtakingly complex problems associated with hydrogen evolution reaction and oxygen evolution reaction. In this context, this critical review gives an overview of the fundamentals of Z-scheme photocatalysis, including both theoretical and experimental advancements in the field of photocatalytic water splitting, and suggests future perspectives.

Photocatalytic Z-Scheme Overall Water Splitting: Recent Advances in Theory and Experiments.

Objectives: The study aimed to develop safe, effective, and targeted drug delivery system for administration of nonsteroidal anti-inflammatory drugs (NSAIDs) in the form of microgels. We de...

Naveed Ahmad

Papers

Photocatalytic Z-Scheme Overall Water Splitting: Recent Advances in Theory and Experiments.

HEMA based pH-sensitive semi IPN microgels for oral delivery; a rationale approach for ketoprofen.