As an alluring metal-free polymeric semiconductor material, graphite-like carbon nitride (g-C
3
N
4
; abbreviated as GCN) has triggered a new impetus in the field of photocatalysis, mainly favoured ...from its fascinating physicochemical and photoelectronic structural features. However, certain inherent drawbacks, involving rapid reassembly of photocarriers, low specific surface area and insufficient optical absorption, limit the wide-range applicability of GCN. Generation of 0D point defects mainly by introducing vacancies (C and/or N) into the framework of GCN has spurred extensive consideration owing to their distinctive qualities to manoeuvre substantially, the optical absorption, radiative carrier isolation, and surface photoreactions. The present review endeavours to summarise a comprehensive study on vacancy defect engineered GCN. Starting from the basic introduction of defects and C/N vacancy modulated GCN, numerous advanced strategies for the controlled designing of vacancy rich GCN have been explored and discussed. Afterwards, light was thrown on the various substantial technologies which are useful for characterising and identifying the introduction of defects in GCN. The salient significance of defect engineering in GCN has been reviewed concerning its impact on optical absorption, charge isolation and surface photoreaction ability. Typically, the achievement of defect engineered GCN has been scrutinised toward various applications like photocatalytic water splitting, CO
2
conversion, N
2
fixation, pollutant degradation, and H
2
O
2
production. Finally, the review ends with conclusions and vouchsafing future challenges and opportunities on the intriguing and emerging area of vacancy defect engineered GCN photocatalysts.
As an alluring metal-free polymeric semiconductor material, graphite-like carbon nitride (g-C
3
N
4
; abbreviated as GCN) has triggered a new impetus in the field of photocatalysis, mainly favoured from its fascinating physicochemical and photoelectronic structural features.
Since it was first discovered, thousands of years ago, silkworm silk has been known to be an abundant biopolymer with a vast range of attractive properties. The utilization of silk fibroin (SF), the ...main protein of silkworm silk, has not been limited to the textile industry but has been further extended to various high-tech application areas, including biomaterials for drug delivery systems and tissue engineering. The outstanding mechanical properties of SF, including its facile processability, superior biocompatibility, controllable biodegradation, and versatile functionalization have allowed its use for innovative applications. In this review, we describe the structure, composition, general properties, and structure-properties relationship of SF. In addition, the methods used for the fabrication and modification of various materials are briefly addressed. Lastly, recent applications of SF-based materials for small molecule drug delivery, biological drug delivery, gene therapy, wound healing, and bone regeneration are reviewed and our perspectives on future development of these favorable materials are also shared.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Solar radiation is a sustainable, unlimited source of energy for electricity and chemical reactions, yet the conversion efficiency of actual processes is limited and controlled by photocarriers ...migration and separation. Enhancing the conversion efficiency would require to suppress the recombination of photogenerated electron–hole pairs and improve the low redox potentials. This can be done during the growth of step-scheme (S-scheme) heterojunctions. Here we review the charge transfer of S-scheme heterojunctions involving a reduction and oxidation photocatalyst in staggered band arrangement with Fermi level differences. We present factors determining the validation of the S-scheme mechanism with respective characterization techniques, including in situ and ex situ experiments, and theoretical studies. We show mechanistic drawbacks of traditional photocatalytic systems to highlight the advantages of S-scheme photocatalysts. We describe co-catalyst loading, bandgap tuning, and interfacial optimization that ultimately achieve highly efficient photocatalysis. Last, application for water splitting, CO
2
conversion, pollutant degradation, bacterial inactivation and others is discussed.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Display omitted
•Cocatalysts in TiO2-based photocatalysts are highlighted for solar hydrogen production.•Design strategies of cocatalysts in TiO2-based photocatalysts are presented ...systematically.•Enhancements are attributed to manipulating the charge separation and surface reactions.•Challenges and perspectives of cocatalysts in TiO2-based photocatalysts are proposed.
TiO2-based photocatalysts have been maintained as the most prominent candidate for solar-driven hydrogen (H2) evolution over the past decades. However, poor separation of generated electron-hole pairs has been considered the bottle-neck issue, restricting the TiO2 activity. Coupling a TiO2 photocatalyst to cocatalyst(s) turns out to be the ideal strategy to suppress the charge recombination and offer robust active centres, boosting the H2 evolution performance. This review aims at providing the frontier investigations of cocatalysts-integrated TiO2 for photo-induced H2 evolution. Four types of cutting-edge development of cocatalysts, including metal (noble metal, non-noble metal, bimetallic), metal sulfides and metal phosphides, 2D-MXenes, and dual materials-based cocatalysts, have been successfully highlighted and discussed. The systematically provided cocatalysts, which remarkably promote the charge separation and facilitate the surface reactions, bring out a roadmap to inspire the preparation of superior TiO2-based materials for H2 evolution shortly. We expect this review could provide enriched information to tailor the TiO2 supported active sites of cocatalysts for highly photo-induced H2 evolution.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
•The challenges in single metal atom catalysts (SACs) are highlighted.•COFs with tailored functionality serve as promising substrates for SACs.•Pore space and organic linkers of COFs ...provide a support to SACs.•Catalytic applications of COFs modified SACs are explored.•Foreseeable challenges and perspectives for COFs modified SACs are proposed.
With the motive of bridging the gap between homocatalysis and heterocatalysis, atomically dispersed single metal atom catalysts (SACs) on different supports have rapidly progressed in the field of catalysis. In recent years, covalent organic frameworks (COFs) have been recognized as promising 2D and 3D crystalline polymers for producing SACs, featured with distinct benefits of porous structure, tailored functionality and high metal loading. The superior efficiency of catalytic reactions in COF modified SACs mainly depends upon the single atom catalytic active sites, ultrafine atomic dispersion of metal atoms, and coordination environment provided by COFs skeleton which collectively determines the electronic properties. This review explores the strategic synthesis routes, advanced characterisation, and catalytic applications of COF-based SACs. The versatile potentials provided by COFs for fulling the prerequisites of SACs formation are discussed. A critical discussion on the strategic synthesis of COF-based SACs is proposed, by exploiting the structural merits of COFs. We summarize the strengths of advanced characterization techniques in identifying the successful construction of SACs. A sketch of the reported work is presented for catalytic energy related applications including photocatalysis, electrocatalysis and carboxylation processes. Also, a suggestive overview on the existing challenges, foresighted ideas and future perspectives for COF-based SACs are mentioned.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
•Selective CO2 photoconversion into C1 and C2 products is emphasised.•Vacancy modulated Bismuth based photocatalysts for CO2 conversion is highlighted.•Substantial engineering methods ...and identification tools for vacancies are explored.•Reaction pathways are presented using experimental and DFT calculation results.•Existing research gaps for scale-up photoconversion efficacy are suggested.
Solar-driven CO2 conversion into value-added C1 and C2 chemicals and fuels offer an attractive route to alleviate global environmental and energy issues. Vacancy modified Bi-based photocatalysts possessing fascinating layered framework, visible-light responsive features, and tunable electronic arrangement, are a preeminent candidate for photocatalytic CO2 conversion. Vacancy engineering in Bi-based materials offers simultaneous modification in the electronic structure, surfacial active sites, and CO2 adsorption/activation kinetics leading to efficacious selective CO2 photoconversion. Herein, the phenomenon of CO2 photoconversion directed by vacancy-modified bismuth-based photocatalysts has been systematically reviewed and presented. Starting from the fundamentals of CO2 photoreduction, the potential role of vacancies in improving CO2 adsorption and activation has been highlighted. Afterward, the advanced characterization tools for the identification of vacancies and various engineering methods for controlled vacancy generation are comprehensively discussed. Also, the impact of vacancy generation on the selective conversion of CO2 into value-added C1 and C2 products has been thoroughly investigated. In conclusion, based on the understanding and relationships of vacancies with photocatalytic properties of bismuth-based materials, existing challenges and foresighted perspectives are mentioned.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Photocatalysts comprising 2D carbon nitride-based systems have emerged as a fervently researched topic for addressing the problems of fuel depletion and the environment. However, the photocatalytic ...activities of pristine g-C
3
N
4
are still mediocre and suffer from issues pertaining to the restrictions in light absorption, charge separation, and carrier-induced surface reactions; however, efforts have been made in the past decades to boost the efficiencies. This review endeavors to present a roadmap to prepare high-performance g-C
3
N
4
photocatalysts by expounding the cutting-edge research on g-C
3
N
4
materials either as a single component or g-C
3
N
4
-based composites including current challenges and perspectives on this topical theme. We believe that this review will provide a broader picture and recommendations for the preparation of superior g-C
3
N
4
photocatalysts towards a greener, cleaner, and resilient future.
This review endeavors to present a roadmap to prepare high-performance g-C
3
N
4
photocatalysts for hydrogen production and environmental remediation.
Photocatalytic hybrid carbon nanotubes (CNTs)–mediated Ag-CuBi
2
O
4
/Bi
2
WO
6
photocatalyst was fabricated using a hydrothermal technique to effectively eliminate organic pollutants from ...wastewater. The as-prepared samples were characterized via Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction patterns (XRD), high-resolution transmission electron microscope (HR-TEM), UV–vis Diffuse Reflectance spectrum (UV–Vis DRS), and photoluminescence (PL) studies. The photocatalytic performance of fabricated pristine and hybrid composites was examined by photo-degradation of toxic dye viz. Rhodamine B (RhB) under visible light. Photo-degradation results revealed that the fabricated Ag-CuBi
2
O
4
/CNTs/Bi
2
WO
6
semiconductor photocatalyst followed pseudo-first-order kinetics and displayed a higher photocatalytic rate, which was found to be approximately 3.33 and 2.35 times higher than the pristine CuBi
2
O
4
and Bi
2
WO
6
semiconductor photocatalyst, respectively. Re-cyclic results demonstrated that the formed composite owns excellent stability, even after five consecutive cycles. As per the matched Fermi level of CNTs in between Ag-CuBi
2
O
4
and Bi
2
WO
6
, carbon nanotubes severed as electron transfer-bridge, Ag doping on CuBi
2
O
4
surface successfully increased photon absorption all across CuBi
2
O
4
surface. Also, it hindered the assimilation of photoinduced electron–hole pairs. The increased photocatalytic efficiency is contributed to the uniform dispersion of photo-generated electron–hole pairs via the construction of an S-scheme system. ROS trapping and ESR experiments suggested that (∙OH) and (O
2
−
∙) were the main radical species for enhanced photo-degradation of RhB dye. The current investigation, from our perspective, highlights the new insights for the fabrication of practical CNTs-mediated S-scheme–based semiconductor photocatalyst for the resolution of environmental issues based on practical considerations.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
