Nanozymes, the enzyme-mimicking nanomaterials, have been developed to overcome the low stability and high cost of natural enzymes. Unlike highly active and specific enzymes, however, the catalytic activities of nanozymes are moderate and lack specificity. To address these issues, herein we demonstrated an effective and general strategy to specifically enhance the peroxidase-mimicking activities of carbon nanozymes. By doping heteroatom nitrogen (N) into reduced graphene oxide (rGO) and mesoporous carbon (MC), their peroxidase-mimicking activities were enhanced by over 100- and 60-fold, respectively. Moreover, N-doping did not significantly affect the oxidase-, superoxide dismutase (SOD)-, or catalase-mimicking activities of rGO and MC, demonstrating a specific enhancement of the peroxidase-mimicking activities. To understand the origin of the specific enhancement, we performed density functional theory calculations to examine the catalytic reaction mechanisms responsible for the peroxidase-, catalase-, oxidase-, and SOD-mimicking activities of N-doped rGO (N-rGO). We revealed that N-rGO selectively activated H2O2 rather than O2 and •O2 – by forming and stabilizing radical oxygen species adjacent to the N sites of N-rGO. The radical oxygen species then oxidized peroxidase substrates, endowing N-rGO with peroxidase-mimicking activity. This study will aid in the rational design of highly active and specific peroxidase mimics and help elucidate the catalytic mechanisms of nanozymes.

Graphene is often regarded as one of the most promising candidates for future nanoelectronics. As an indispensable component in graphene-based electronics, the formation of junctions with other materials not only provides utility functions and reliable connexions, but can also improve or alter the properties of pristine graphene, opening up possibilities for new applications. Here we demonstrate an intramolecular junction produced by the controllable unzipping of single-walled carbon nanotubes, which combines a graphene nanoribbon and single-walled carbon nanotube in a one-dimensional nanostructure. This junction shows a strong gate-dependent rectifying behaviour. As applications, we demonstrate the use of the junction in prototype directionally dependent field-effect transistors, logic gates and highperformance photodetectors, indicating its potential in future graphene-based electronics and optoelectronics.

The discovery of short-range order, associated with diffuse bands in electron diffraction patterns, provides new insights into defective half-Heusler thermoelectric crystals.

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Half-Heusler and full-Heusler compounds were considered as independent phases with a natural composition gap. Here we report the discovery of TiRu1+xSb (x = 0.15 ~ 1.0) solid solution with wide homogeneity range and tunable p- to n-type semiconducting thermoelectrics, which bridges the composition gap between half- and full-Heusler phases. At the high-Ru end, strange glass-like thermal transport behavior with unusually low lattice thermal conductivity (~1.65 Wm−1K−1 at 340 K) is observed for TiRu1.8Sb, being the lowest among reported half-Heusler phases. In the composition range of 0.15 < x < 0.50, TiRu1+xSb shows abnormal semiconducting behaviors because tunning Ru composition results in band structure change and carrier-type variation simultaneously, which seemingly correlates with the localized d electrons. This work reveals the possibility of designing fascinating half-Heusler-like materials by manipulating the tetrahedral site occupancy, and also demonstrates the potential of tuning crystal and electronic structures simultaneously to realize intriguing physical properties.

Cubic half‐ and full‐Heusler compounds with respectively 18 and 24 valence electrons exhibit semiconducting behaviors according to the Slater–Pauling rule. In this work, a half‐Heusler‐like ZrRu1.5Sb semiconductor with the space group Ftrue4¯3m is discovered based on the Slater–Pauling rule. The ZrRu1.5Sb compound has 21 valence electrons per chemical formula and each atom has six valence electrons on average, showing a p‐type conduction with a dimensionless thermoelectric figure of merit zT ≈0.2 at 973 K. By adjusting the Ru content, both p‐type (x ≤ 0.5) and n‐type (x > 0.5) semiconductors are realized in the ZrRu1+xSb solid solution. Following this way, other half‐Heusler‐like semiconductors, such as ZrRu1.30Ni0.10Sb, ZrRu1.40Ni0.05Sb, and ZrRu1.30Ni0.05Sb, are also successfully designed and synthesized, demonstrating the effectiveness and practicality of our strategy to explore Slater–Pauling semiconductors. Furthermore, these half‐Heusler‐like semiconductors show promising potential as thermoelectric materials. The p‐type ZrRu1.4Sb and n‐type ZrRu1.7Sb samples have zT values of 0.38 at 973 K and 0.25 at 773 K, respectively, offering superior base materials for further optimizing their thermoelectric properties. The discovery of ZrRu1.5Sb‐based thermoelectric semiconductors demonstrates the great potential to design Slater–Pauling phases with exotic physical properties.

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