Visible light promoted aerobic selective photo-oxidation of cyclohexene on LaCo_(x)Cu_(1−x)O_(3) catalyst

Heterogeneously catalyzed liquid oxidation of olefins with O_(2) provides an alternative way for synthesizing high-value added chemicals.Herein,we report a straightforward urea-redox and sol-gel process for synthesizing LaCo_(x)Cu_(1−x)O_(3) for aerobic photooxidation of cyclohexene.Our research highlights a marked increase in the proportions of Co^(2+) and Cu+species in a low chemical state,as well as enhanced visible light absorption through this method.Mechanistic investigations suggest that the catalytic process,particularly with LaCo_(0.7)Cu_(0.3)O_(3),involves a radical pathway mediated by reactive oxygen species.The presence of Cu+/Co^(2+) species and surface oxygen vacancies is proposed to boost O_(2) adsorption and activation on the catalyst,facilitating the formation of 2-cyclohexene-1-hydroperoxides.Furthermore,Cu^(2+)/Co^(3+) species are thought to aid in generating cyclohexenederived radical species.The efficient aerobic oxidation of cyclohexene on LaCo_(0.7)Cu_(0.3)O_(3) catalyst relies on the formation of reactive oxygen species and carbon radicals,facilitated by its strong visible light illumination.It achieves a cyclohexene conversion of 89.4% and selectivity to cyclohex-2-ene-1-one of 72.2%,along with stable recyclability after six reuses.The creation of nano-structured LaCo_(x)Cu_(1−x)O_(3) through the urea-redox and sol-gel process offers a promising avenue for the development of highly efficient catalysts for the aerobic photo-oxidation of cyclohexene to cyclohex-2-ene-1-one in the future.

Hexagonal boron nitride nanomaterials for biomedical applications

Hexagonal boron nitride(h-BN)nanomaterials are a rising star in the field of biomedicine.This review presents an overview of the progress in h-BN nanomaterials for biological applications.It begins with a general introduction of the structural characteristics of h-BN,followed by the brief introduction of its physical and chemical properties,including thermal,band and mechanical properties,chemical reactivity,biodegradability and biocompatibility,then emphasizes on the recent progress in the biomedical applications including drug delivery,boron neutron capture therapy(BNCT),bioimaging and nanozyme,and ends with the challenges and perspectives related to the biomedical applications.The advantages of BN nanomaterials used for biomedical applications were analyzed,and their problems were also discussed,inspiring the future rational designs of the BN nanomedicines.

Jahn-Teller distortion assisted interstitial nitrogen engineering:Enhanced oxygen dehydrogenation activity of N-doped Mn_(x)Co_(3-x)O_(4) hierarchical micro-nano particles

Rational design of earth-abundant transition metal oxides catalysts is highly desirable for developing sustainable chemical processes.Herein,we demonstrate a prospective interstitial nitrogen engineering for fabricating oxygen vacancies(OVs)-rich nitrogen-doped-Mn_(x)Co_(3-x)O_(4)(N-Mn_(x)Co_(3-x)O_(4))oxide catalyst,in which the ratio of OVs concentration of N-Mn_(x)Co_(3-x)O_(4)to Mn species is as high as 1:1,according to the characterizations of X-ray absorption(XAS)and X-ray photoelectron(XPS)spectroscopies.The promising strategy of interstitial nitrogen engineering through lattice distortion caused by the Jahn-Teller effect can significantly increase the amount of interstitial nitrogen.The resulting catalyst enables an additive-free aerobic dehydrogenation coupling of aromatic amine to afford azo compounds with>99%yield and>99%selectivity at 60☆.We observed the superb catalytic activity is promoted by the enhanced oxygen mobility in OVs,which were created by the interstitial nitrogen in the catalyst matrix.The presence of interstitial nitrogen in transition metal oxides in this study shows how the manipulation of catalyst matrix can increase the OV sites to promote aerobic oxidation reaction.

Revealing efficient catalytic performance of N-CuO_(x) for aerobic oxidative coupling of aliphatic alkynes:A Langmuir-Hinshelwood reaction mechanism

O_(x)idative couplings of aliphatic alkynes are crucial for the production of naturally occurring 1,3-diynes.Herein we report the novel approach for effective synthesis of unsaturated coordinated N doped copper oxides(N-CuO_(x))catalyst,and uncover that N-CuO_(x) catalyst as an additive-free and cost-effective heterogeneous catalyst has highly catalytic performance for directly oxidative coupling of aliphatic alkynes.The key to achieve efficient oxidative coupling of aliphatic alkynes is the synergistic effect of N species and uncoordinated O/Cu species caused by N dopants,which undergoes the Langmuir–Hinshelwood reaction mechanism.The N-CuO_(x) catalyst displays~89.1%yield for hexadeca-7,9-diyne under mild conditions and stable reusability(5 cycles),showing significant advances compared with the traditionally copper oxides.These findings highlight the heteroatom dopants that provide a new methodology for designing efficient copper catalysts in synthesis of naturally occurring 1,3-diynes.