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Highlights: A unique atomic dispersed hetero-pair was successfully synthesized, consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This strategy breaks the linear scaling relationships of electrocatalytic CO2 reduction by simultaneously regulating the *COOH adsorption energy and *CO desorption energy. The as-prepared MoFe–N–C exhibits excellent performance for CO2RR to CO with a high turnover frequency (TOF) of 3336.21 h−1, CO Faradaic efficiency (FECO) of 95.96% at − 0.60 V (versus RHE) and outstanding stability. Electrochemical carbon dioxide reduction reaction (CO2RR) involves a variety of intermediates with highly correlated reaction and ad-desorption energies, hindering optimization of the catalytic activity. For example, increasing the binding of the *COOH to the active site will generally increase the *CO desorption energy. Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO2RR, but remains an unsolved challenge. Herein, we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This system shows an unprecedented CO2RR intrinsic activity with TOF of 3336 h−1, high selectivity toward CO production, Faradaic efficiency of 95.96% at − 0.60 V and excellent stability. Theoretical calculations show that the Mo-Fe diatomic sites increased the *COOH intermediate adsorption energy by bridging adsorption of *COOH intermediates. At the same time, d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of *CO intermediates. Thus, the undesirable correlation between these steps is broken. This work provides a promising approach, specifically the use of di-atoms, for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale. [ABSTRACT FROM AUTHOR]

An examination of the effect of B- and P-doping and codoping on the electronic structure of anatase TiO2 by performing density functional theory calculations revealed the following: (i) B- or P-doping effects are similar to atomic undercoordination effects on local bond relaxation and core electron entrapment; (ii) the locally entrapped charge adds impurity levels within the band gap that could enhance the utilization of TiO2 to absorb visible light and prolong the carrier lifetime; (iii) the core electron entrapment polarizes nonbonding electrons in the upper edges of the valence and conduction bands, which reduces not only the work function but also the band gap; and (iv) work function reduction enhances the reactivity of the carriers and band gap reduction promotes visible-light absorption. These observations may shed light on effective catalyst design and synthesis. [ABSTRACT FROM AUTHOR]

The front cover artwork is provided by Prof. Wei Zhang and Cai Zhang from Jilin University (Changchun, China). The image shows that heat treatment can govern the bonding states and unlock the ORR activity for nitrogen-doped amorphous carbon, which is an analogy to the beauty of the stained-glass windows of Sagrada Família Basílica (Barcelona, Spain) revealed by the sunlight streaming through the windows. Read the full text of the Communication at . [ABSTRACT FROM AUTHOR]

Synthesized by dripping iron acetate into the N-doped carbon film enriched with pyridinic N and followed by annealing at 800 °C, Fe–N-doped amorphous carbon (d Fe–N -C) with an Fe content of 0.2 at.% showed excellent electrocatalytic activity, stability and methanol tolerance via a four-electron pathway for oxygen reduction reaction (ORR), which outperformed commercial Pt/C catalyst. More importantly, by tuning the Fe content and annealing temperature, the trace Fe in d Fe–N -C was supposed to form high active FeN 4 sites with pyridinic N and played an important role in the excellent electrocatalytic performance for ORR. [ABSTRACT FROM AUTHOR]

(Ba 1− x Nd x ) (Ti 0.97 Mn 0.03 )O 3 (BNTM) ( x  = 0.01, 0.02, 0.04, 0.06) ceramics were prepared using a conventional cold-pressing ceramic technique. The structure, valence state and dielectric properties were investigated using XRD, RS, SEM, TEM, EPR, and dielectric temperature and frequency measurements. XRD, RS analysis coupled with SEM and TEM observations indicate that the samples have a coexistence of tetragonal and hexagonal phase at room temperature as x  ≤ 0.02 and become a single phase in the tetragonal as x  = 0.04 and in the cubic as x  = 0.06 (air-sintered, 1400 °C/12 h). It reveals that Nd 3+ ions can suppress hexagonal phase effectively and benefit the formation of single-phase ceramics. Improvement of dielectric properties is accompanied by the structural evolution. Particularly a cubic ceramic with x  = 0.06, the dielectric-peak temperature is found to shift to room temperature, meeting the EIA Y5V specification with tan δ < 0.04. Up to x = 0.04, the phase transition remains first order. The valence state of Mn ions was analyzed by EPR. It is found that Mn ions transform from high valence (+3 and + 4) to low valence (+2) with the increase of Nd concentration, and all of the Mn ions exist as Mn 2+ when x  = 0.06. The unit cell volume and dielectric-peak temperature of BNTM decrease nonlinearly with increasing x , which can be ascribed to the incorporation of Nd ions and the formation of 2 N d B a · − M n T i ″ donor-acceptor defect complexes. [ABSTRACT FROM AUTHOR]

N, S co-doped graphene quantum dots (N, S-GQDs) -reduced graphene oxide- (rGO) -TiO 2 nanotubes (TiO 2 NT) composites were prepared by a facile alkaline hydrothermal reaction and physical stirring process. The apparent rate constant of the N, S-GQDs+10%rGO + TiO 2 NT composite, exhibiting the highest photodegradation efficiency, is 1.8 times and 16.3 times higher than those of 10%rGO + TiO 2 NT and pure TiO 2 NT, respectively, for the degradation of methyl orange (MO) under visible light irradiation (λ > 400 nm). Our work could provide new insights into the fabrication of GQDs-semiconductor composites as high performance photocatalysts and broaden the range of doped GQDs widely used for environmental protection. [ABSTRACT FROM AUTHOR]

Abstract: Transition metal is usually required for obtaining N-doped carbon (dN-C) catalysts toward oxygen reduction reaction, leading to an intense debate on whether the active sites in dN-C correlate to transition metal. Here, we report that metal-free amorphous dN-C was synthesized using simple one-step magnetron sputtering at relatively low temperature. The chemical bonding states of N atoms, which play a key role in optimizing the electrocatalytic activity, can be tuned by adjusting deposition temperature. The metal-free dN-C with high pyridinic N content exhibits high electrocatalytic activity, and its stability and methanol tolerance are much better than commercial Pt/C catalyst. [Copyright &y& Elsevier]