{"title":"Effect of precursors on the structure and photocatalytic performance of g-C3N4 for NO oxidation and CO2 reduction","authors":"","doi":"10.1016/j.cjsc.2024.100416","DOIUrl":"10.1016/j.cjsc.2024.100416","url":null,"abstract":"<div><div>Graphitic carbon nitride (g-C<sub>3</sub>N<sub>4</sub>, CN) is recognized as the most extensively studied organic polymeric photocatalyst for pollution control and energy conversion due to its facile synthesis and suitable electronic band structure. The aim of the present work is to explore the effect of precursors, such as urea (U, (NH<sub>2</sub>)<sub>2</sub>CO), dicyandiamide (D, C<sub>2</sub>H<sub>4</sub>N<sub>4</sub>) and melamine (M, C<sub>3</sub>H<sub>6</sub>N<sub>6</sub>), on the structure and photocatalytic activity of the obtained CN samples, denoted as UCN, DCN and MCN, respectively. The sheet-like UCN sample shows significantly enhanced photoreactivity in both NO oxidation and CO<sub>2</sub> reduction compared to the bulk DCN and MCN materials. In addition, UCN demonstrates the ability to suppress the formation of toxic NO<sub>2</sub> intermediate during the photocatalytic oxidation of NO. The improved photocatalytic activity of UCN can be attributed to a dual effect: first, its increased specific surface area provides more active sites for the photocatalytic reaction; second, it exhibits a stronger affinity for substrates like NO and CO<sub>2</sub>, which facilitates charge migration at the interface.</div></div>","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223454","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nitrogen doping retrofits the coordination environment of copper single-atom catalysts for deep CO2 reduction","authors":"","doi":"10.1016/j.cjsc.2024.100415","DOIUrl":"10.1016/j.cjsc.2024.100415","url":null,"abstract":"<div><div>The electrocatalytic CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) represents an effective way to address energy crises and environmental issues by converting CO<sub>2</sub> into valuable chemicals. Single-atom catalysts (SACs) can achieve excellent catalytic activity in CO<sub>2</sub>RR. However, the study of CO<sub>2</sub>RR on SACs still poses significant challenges, especially in terms of controlling the selectivity towards the deep product such as CH<sub>4</sub> and CH<sub>3</sub>OH. Herein, we employ density functional theory (DFT) calculations to investigate the CO<sub>2</sub>RR on Cu SAC supported on N-doped graphene (Cu-N/C) and explore the role of N dopants on the CO<sub>2</sub>RR performance. Compared to Cu SACs supported on N-doped defective graphene with double vacancy (Cu-N/C-DV), Cu SACs supported on N-doped defective graphene with single vacancy (Cu-N/C-SV) can effectively convert CO<sub>2</sub> into the deeply reduced C<sub>1</sub> products, including CH<sub>4</sub> and CH<sub>3</sub>OH, thus further indicating that Cu-N/C-SV has a stronger interaction with ∗CO, which is conducive to the deep reduction of ∗CO. Increasing the coordination number of N atoms or the proximity of doping site to the Cu active site can effectively enhance the stability of catalyst and promote the adsorption of ∗CO on Cu-N/C-SV. However, this also increases the free energy of the formation of ∗CHO intermediate. The results suggest that CuC<sub>3</sub>-N<sub>m</sub>, which contains a N atom in the second coordination shell (meta-position) of Cu SACs, has the best electrocatalytic performance of CO<sub>2</sub>RR in terms of both selectivity and catalytic activity, not only contributing to an in-depth understanding of the reaction mechanism of CO<sub>2</sub>RR on SACs but also providing insights into the design of SACs for efficient CO<sub>2</sub>RR.</div></div>","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142177538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Dynamic photoluminescence switching of carbon nitride thin films for anticounterfeiting and encryption","authors":"","doi":"10.1016/j.cjsc.2024.100410","DOIUrl":"10.1016/j.cjsc.2024.100410","url":null,"abstract":"<div><p>Photoluminescence (PL) has been increasingly applied in anticounterfeiting and encryption as counterfeiting becomes more prevalent. However, common luminescent encryption techniques are based on static PL measurements and are easy to counterfeit. In this work, we have developed a thermal vapor deposition (TVD) approach using melem as the unique starting material to synthesize highly homogeneous carbon nitride (CN) thin films featuring unique dynamic PL switching properties. After being irradiated by a white LED, the blue PL intensity of the CN film increases significantly and then fades in darkness, demonstrating excellent recyclability. Experimental results prove that CN films contain cyano groups in the structure, and density functional theory (DFT) calculations indicate that the integration of cyano groups results in traps within the bandgap of CN, suggesting that the dynamic PL switching effect is essentially associated with the fullness of the trap states. We have therefore developed an advanced luminescent device for the secure transmission of encrypted information through controlled illumination. It can be easily read with a portable UV (365 nm) lamp and effectively erased using the white LED, thereby preventing information leakage and showing great potential for many applications.</p></div>","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0254586124002733/pdfft?md5=1f137ee929ade0567085104ce2dada7b&pid=1-s2.0-S0254586124002733-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mesoporous CuCe dual-metal catalysts for efficient electrochemical reduction of CO2 to methane","authors":"","doi":"10.1016/j.cjsc.2024.100350","DOIUrl":"10.1016/j.cjsc.2024.100350","url":null,"abstract":"","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141133269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Ni-based electrocatalysts for urea-assisted water splitting","authors":"","doi":"10.1016/j.cjsc.2024.100373","DOIUrl":"10.1016/j.cjsc.2024.100373","url":null,"abstract":"","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Deciphering the structural evolution and real active ingredients of iron oxides in photocatalytic CO2 hydrogenation","authors":"","doi":"10.1016/j.cjsc.2024.100348","DOIUrl":"10.1016/j.cjsc.2024.100348","url":null,"abstract":"<div><p>Photocatalytic CO<sub>2</sub> hydrogenation reactions can produce high-value-added chemicals for industry, solving the environmental problems caused by excessive CO<sub>2</sub> emissions. Iron oxides are commonly used in photocatalytic reactions due to their various structures and suitable band gaps. Nevertheless, the structural evolution and real active components during photocatalytic CO<sub>2</sub> hydrogenation reaction are rarely studied. Herein, a variety of iron oxides including <em>α</em>-Fe<sub>2</sub>O<sub>3</sub>, <em>γ</em>-Fe<sub>2</sub>O<sub>3</sub>, Fe<sub>3</sub>O<sub>4</sub> and FeO were derived from Prussian blue precursors to investigate the CO<sub>2</sub> hydrogenation performance, structural evolution and active components. Especially, the typical <em>α</em>- and <em>γ</em>-Fe<sub>2</sub>O<sub>3</sub> are converted to Fe<sub>3</sub>O<sub>4</sub> during the reaction, while Fe/Fe<sub><em>x</em></sub>O<sub><em>y</em></sub> remains structurally stable. Meanwhile, it is confirmed that Fe<sub>3</sub>O<sub>4</sub> is the main active component for CO production and the formation of hydrocarbons (CH<sub>4</sub> and C<sub>2</sub>–C<sub>4</sub>) are highly dependent on the Fe/Fe<sub><em>x</em></sub>O<sub><em>y</em></sub> heterojunctions. The optimal yields of CO, CH<sub>4</sub> and C<sub>2</sub>–C<sub>4</sub> hydrocarbons over the best catalyst (FeFe-550) can achieve 4 mmol g<sup>−1</sup> h<sup>−1</sup>, 350 μmol g<sup>−1</sup> h<sup>−1</sup> and 150 μmol g<sup>−1</sup> h<sup>−1</sup>, respectively due to their suitable metal/oxide component distribution. This work examines the structural evolution of different iron oxide catalysts in the photocatalytic CO<sub>2</sub> hydrogenation reaction, identifies the active components as well as reveals the relationship between components and the products, and offers valuable insights into the efficient utilization of CO<sub>2</sub>.</p></div>","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141143924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"All in one doubly pillared MXene membrane for excellent oil/water separation, pollutant removal, and anti-fouling performance","authors":"","doi":"10.1016/j.cjsc.2024.100355","DOIUrl":"10.1016/j.cjsc.2024.100355","url":null,"abstract":"<div><p>Given the diversity and complexity of coexisting oil/dyes/heavy metal ions/microorganisms in wastewater and volatile organic compounds (VOCs) in the air, developing separation materials featured in higher separation efficiency and lower energy consumption for oil and water separation, pollutant removal, and anti-fouling is urgently needed, but it remains a major challenge till now. Herein, a multifunctional Ti<sub>3</sub>C<sub>2</sub> MXene membrane with unique double pillar support was proposed by liquid phase ultrasonication and vacuum filtration to overcome the above challenge. Introducing cetyl-trimethyl ammonium bromide (CTAB) and calcium chloride/sodium alginate (CaCl<sub>2</sub>/SA) to the MXene membrane as crossed double pillars and superhydrophilic surface increases the tolerance and wettability of the membrane. The fabricated doubly pillared MXene (d-Ti<sub>3</sub>C<sub>2</sub>) membrane exhibits superior oil/water (O/W) separation efficiency (99.76%) with flux (1.284 L m<sup>−2</sup> h<sup>−1</sup>) for canola oil and organic dye removing efficiency for methyl blue (MB) 99.85%, malachite green (MG) 100%, and methyl violet (MV) 99.72%, respectively, which is 1.05, 1.44, 1.22, and 1.28 fold compared with pre-pillared Ti<sub>3</sub>C<sub>2</sub> (p-Ti<sub>3</sub>C<sub>2</sub>). The superior anti-oil/dye/fouling is attributed to lower oil conglutination, high hydrophily, and antibacterial activity. The versatile MXene membrane also shows distinguished separation of VOCs (<em>η</em> > 99%) from polluted air. The experimental and molecular dynamics (MD) computational simulation results illustrate that the superior separation efficiency of the Ti<sub>3</sub>C<sub>2</sub> MXene membrane is ascribed to the unique doubly pillared space channel. This study paves a new road to further research on one step integration strategy for complex O/W separation, wastewater and VOCs removal, and anti-fouling via tuning nano/macro architecture.</p></div>","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Insight into stable, concentrated radicals from sulfur-functionalized alkyne-rich crystalline frameworks and application in solar-to-vapor conversion","authors":"","doi":"10.1016/j.cjsc.2024.100380","DOIUrl":"10.1016/j.cjsc.2024.100380","url":null,"abstract":"<div><p><span>Organic radicals feature versatile unpaired electrons<span> key for photoelectronic<span><span> and biomedical applications but remain difficult to access in stable concentrated forms. We disclose easy generation of stable, concentrated radicals from various alkynyl phenyl motifs, including 1) sulfur-functionalized alkyne-rich organic linkers in crystalline frameworks; 2) the powders of these molecules alone; 3) simple diethynylbenzenes. For Zr-based framework, the generation of radical-rich crystalline framework was achieved by thermal annealing in the range of 300–450 °C. For terminal alkynes, </span>electron paramagnetic resonance signals (EPR, indicative of free radicals) arise after air exposure or mild heating (</span></span></span><em>e.g.</em>, 70 °C). Further heating (<em>e.g.</em>, 150 °C for 3 h) raises the radical concentrations up to 3.30 mol kg<sup>−1</sup>. For more stable internal alkynes, transformations into porous radical solids can also be triggered, albeit at higher temperatures (<em>e.g.</em><span>, 250–500 °C). The resulted radical-containing solids are porous, stable to air as well as heat (up to 300–450 °C) and exhibit photothermal conversion<span><span> and solar-driven water evaporation capacity. The formation of radicals can be ascribed to extensive </span>alkyne<span> cyclizations, forming defects, dangling bonds and the associated radicals stabilized by polycyclic π-systems.</span></span></span></p></div>","PeriodicalId":10151,"journal":{"name":"Chinese Journal of Structural Chemistry","volume":null,"pages":null},"PeriodicalIF":5.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141512243","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}