Direct CO2 hydrogenation to methanol using renewable energy–generated hydrogen is attracting intensive attention, but qualifying catalysts represents a grand challenge. Pure-/multi-metallic systems used for this task usually have low catalytic activity. Here, we tailored a highly active and selective InNi3C0.5/ZrO2 catalyst by tuning the performance-relevant electronic metal-support interaction (EMSI), which is tightly linked with the ZrO2 type–dependent oxygen deficiency. Highly oxygen-deficient monoclinic-ZrO2 support imparts high electron density to InNi3C0.5 because of the considerably enhanced EMSI, thereby enabling InNi3C0.5/monoclinic-ZrO2 with an intrinsic activity three or two times as high as that of InNi3C0.5/amorphous-ZrO2 or InNi3C0.5/tetragonal-ZrO2. The EMSI-governed catalysis observed in the InNi3C0.5/ZrO2 system is extendable to other oxygen-deficient metal oxides, in particular InNi3C0.5/Fe3O4, achieving 25.7% CO2 conversion with 90.2% methanol selectivity at 325°C, 6.0 MPa, 36,000 ml gcat−1 hour−1, and H2/CO2 = 10:1. This affordable catalyst is stable for at least 500 hours and is also highly resistant to sulfur poisoning.

Oxygen-deficient metal oxides supported nano-intermetallic InNi3C0.5 toward efficient CO2 hydrogenation to methanol.

Simultaneous detection of dual biomarkers using hierarchical MoS2 nanostructuring and nano-signal amplification-based electrochemical aptasensor toward accurate diagnosis of prostate cancer.

Simultaneous detection of dual biomarkers using hierarchical MoS2 nanostructuring and nano-signal amplification-based electrochemical aptasensor toward accurate diagnosis of prostate cancer

Nanomaterials with enzyme-like activity (nanozymes) have been of great interest in broad applications ranging from biosensing to biomedical applications. Despite that much effort has been devoted to the development of the synthesis and applications of nanozymes, it is essential to understand the interactions between nanozymes and most commonly used biomolecules, i.e., avidin, streptavidin (SA), bovine serum albumin (BSA), immunoglobulin G (IgG), and glutathione (GSH), yet they have been rarely explored. Here, a series of bio-nano interfaces were constructed through direct immobilization of proteins on a variety of iron oxide and carbon-based nanozymes with different dimensions, including Fe3O4 nanoparticles (NPs, 0D), Fe3O4@C NPs (0D), Fe3O4@C nanowires (NWs, 1D), and graphene oxide nanosheets (GO NSs, 2D). Such interfaces enabled the modulation of the catalytic activities of the nanozymes with varying degrees, which allowed a good identification of multiplex proteins with high accuracy. Given the maximum inhibition on Fe3O4@C NP by BSA, we established molecular switches based on aptamer and toehold DNA, as well as Boolean logic gates (AND and NOR) in response to both DNA and proteins. Also importantly, we developed an on-particle reaction strategy for colorimetric detection of GSH with ultrahigh sensitivity and good specificity. The proposed sensor achieved a broad dynamic range spanning 7 orders of magnitude with a detection limit down to 200 pg mL-1, which was better than that of an in-solution reaction-based biosensor by 2 orders of magnitude. Furthermore, we explored the mechanisms of the interactions at bio-nano interfaces by studying the interfacial factors, including surface coverage, salt concentration, and the curvature of the nanozyme. This study offered new opportunities in the elaborate design and better utilization of nanozymes for bioanalysis in clinical diagnosis and in vivo detection.

Construction of Bio-Nano Interfaces on Nanozymes for Bioanalysis.

A new compound of BiLa1.4Ca0.6O4.2 is synthesized through solid state reaction, where the Ca substitutes, in part, the La site in a stable BiLa2O4.5 phase. The structure of the BiLa1.4Ca0.6O4.2 crystallizes in space group R3mH with a hexagonal lattice constants of a = 3.893(1) A, c = 9.891(1) A. Its optical absorption edge is about 2.05 eV, which just spans the visible light region. The photocatalytic activity of the BiLa1.4Ca0.6O4.2 powder to degradation of RhB under visible light irradiation is measured and improved more than 7 times by annealing in nitrogen ambient, indicating that annealing in nitrogen can effectively improve the photocatalytic activity by producing oxygen vacancy. Although the absolute photocatalytic activity obtained is low, there is great potential for enhancing the activity such as nanoscaling, doping, and coupling with other compounds.

A new Bi-based visible-light-sensitive photocatalyst BiLa1.4Ca0.6O4.2: crystal structure, optical property and photocatalytic activity.

The interfacial stability of copper/diamond directly affects its mechanical properties and thermal conductivity. The atomic structures and electronic properties of Cu/diamond and Cu/X/diamond interfaces have been identified to investigate the effect of interfacial additive X (X = Ni or N) on the low-index interfacial adhesion of copper/diamond composites. For unmodified composites, the interfacial stability decreases in the order of Cu(001)/diamond(001) > Cu(111)/diamond(111) > Cu(011)/diamond(011). The metallic interfacial additive Ni is found to enhance the Cu(011)/diamond(011) interfacial stability and exchange the interfacial stability sequence of (011) and (111) composites. The nonmetallic element N will promote the stability of Cu(111)/diamond(111) but not alter the stability order of the composites at different interface. To explain the origin of interfacial stability, a series of analyses on atomic structures and electronic properties have been carried out, including the identification of the type of formed interfacial boundary, the measurement of interfacial bond lengths, and the calculations of density of states, bond populations, and atomic charge. The stability of the interface is found to be related to the type of formed interfacial boundary and bond, the interfacial bond populations, and the interfacial bond numbers. The LPDOS reveals that all of the considered interfaces exhibit metallic character. The interfacial Ni additive is found to be an electron donor contributing the electrons to its bonded Cu and C atoms while interfacial N atom is an electron acceptor where it mainly accepts the electrons from its bonded Cu and C.

https://iopscience.iop.org/article/10.1088/1361-648X/ab686b/pdf

Atomic structures and electronic properties of Ni or N modified Cu/diamond interface.

Novel ternary intermetallic compounds La2Co17-xMx (M = Nb, Mo, Mn) with Th2Zn17-type structure were synthesized and their homogeneous ranges were determined: 0.3 less than or equal to x less than or equal to 0.6 for Nb, 0.6 less than or equal to x less than or equal to 1.2 for Mo and 1.0 less than or equal to x less than or equal to 4.0 for Mn. The lattice parameters and the unit-cell volume increase with increasing x in all of the systems. The preferential occupancy of 6c crystallographic positions (dumb-bell sites) and the stabilization of these compounds by M atoms are attributed to the atomic-size and enthalpy effects. These compounds exhibit favourable uniaxial anisotropy with M content x greater than or equal to 0.5. The Curie temperature decreases monotonically with increasing x for all of the systems. The saturation moment , decreases rapidly with increasing x for M = Mo and Nb. In the La2Co17-xMnx system, mu(s) increases slightly with x for x less than or equal to 2.5 and then decreases for x > 2.5.

https://iopscience.iop.org/article/10.1088/0953-8984/11/48/336/pdf

Crystal structure and magnetic properties of the intermetallic compounds La2Co17-xMx (M = Nb, Mo, Mn)

Visible light-driven H2O2 production presents the unique merits of sustainability and environmental friendliness. The size of noble metal nanoparticles (NPs) determines their dispersion and electronic structure and greatly affects their photocatalytic activity. In this work, a series of sized Au NPs over C3N4 were modulated for H2O2 production. The results show that there is a volcanic trend in H2O2 with the decrease of Au particle size, and the highest H2O2 production rate of 1052 μmol g-1 h-1 is obtained from medium-sized Au particles (∼8.7 nm). The relationship between structure and catalytic performance is supported by experimental and theoretical methods. (1) First, medium-sized Au NPs promote photon absorption, and have a suitable built-in electric field at the heterojunction, which can be successfully tuned to achieve a more efficient h+-e- spatial separation. (2) Second, medium-sized Au NPs enhance O2 adsorption, and create selective 2e- O2 reduction reaction sites. (3) Particularly, medium-sized Au NPs promote the desorption of produced H2O2 and inhibit H2O2 decomposition, finally leading to the highest H2O2 selectivity. Excellent catalytic performance will be obtained by finely optimizing the particle size in a certain range. This work provides a new idea for preparing high efficiently photocatalysts for H2O2 production.

Visible light-driven H2O2 synthesis over Au/C3N4: medium-sized Au nanoparticles exhibiting suitable built-in electric fields and inhibiting reverse H2O2 decomposition.

First-principles study of the surface structure and stability of BC 5

Fe-based MOFs (Fe-MOFs) are deemed promising Fenton-like catalysts due to their well-developed pores and accessible active sites. However, their inferior catalytic activity, iron leaching, and low H2O2 utilization always hinder their application as Fe-based MOF catalysts. In this work, we manipulated the structure of Fe-oxo nodes in MIL-88B(Fe) via a CuI species substitution method, affording a mixed-valence (Cu-incorporated Fe-MOFs) with highly improved Fenton-like performance. It is found that the CuI serves as a shuttle to promote transfer between FeII/FeIII, inducing the formation of a larger amount of stable FeII sites, which was proven by experimental and DFT calculation results. A linear relationship was observed for the Fenton-like performance and the amount of CuI species for the catalysts. The corresponding value of the •OH formation is 2.17 eV for Cu-incorporated MIL-88B(Fe), which is significantly lower than that of MIL-88B(Fe) (2.69 eV). Meanwhile, the enriched CuI species suppress Fe species leaching during the catalytic reaction. The Fe-ion leakage of 0.4Cu@MIL-88B is very tiny (0.01-0.03 mg/L), significantly less than that of MIL-88B (2.00-3.02 mg/L). At the same time, H2O2 utilization for 0.4Cu@ MIL-88B(Fe) is 88%, which is almost 4.4 times that of pure MIL-88B(Fe). This work provides insights into the rational design of Fe-MOFs as promising Fenton-like catalysts for wastewater treatment.

Yanyan Chen

Papers

Atomic structures and electronic properties of Ni or N modified Cu/diamond interface.

Crystal structure and magnetic properties of the intermetallic compounds La2Co17-xMx (M = Nb, Mo, Mn)

Visible light-driven H2O2 synthesis over Au/C3N4: medium-sized Au nanoparticles exhibiting suitable built-in electric fields and inhibiting reverse H2O2 decomposition.

First-principles study of the surface structure and stability of BC 5

Effects and Mechanisms of Cu Species in Fe-MOFs on Fenton-Like Catalytic Activity and Stability.