RESUMEN
With the increasing presence of blockchain-based distributed applications in various aspects of daily life, there has been a growing focus on the privacy protection of blockchain ledgers and the corresponding regulatory technologies. However, current mainstream solutions primarily concentrate on the verifiable encryption of blockchain transaction addresses and contents, neglecting the regulatory requirements for private transactions. Moreover, the few monitorable solutions suffer from issues such as excessive centralization and a single-minded approach to regulatory content. To address these deficiencies, this paper proposes a blockchain privacy-preserving scheme that supports multi-level regulation through the utilization of zero-knowledge proofs (zk-SNARKs) and attribute-based encryption (ABE). Firstly, by leveraging zk-SNARKs, this scheme achieves blockchain privacy-preserving within an account model, enabling the concealment of user transaction addresses and values. Secondly, by employing attribute-based encryption, a multi-level regulatory model is developed alongside the privacy protection measures, allowing for selective disclosure of transaction content. Finally, we analyze the security of the proposed scheme and compare it with other schemes, discussing its advantages in terms of privacy, security, and regulatory capabilities, we also provide a preliminary evaluation of the scheme's efficiency through experiments. In conclusion, the scheme demonstrates strong privacy by relying on mathematical proofs through zk-SNARKs to ensure security while comprehensively safeguarding content. It also achieves multi-level regulation on the foundation of privacy protection, with comprehensive regulatory coverage and decentralized regulatory authority.
RESUMEN
The stacking of Ti3C2 with transition metal dihalide (TMDs) materials is an effective strategy to improve the physical properties of a single material, and the tuning of the related properties of these TMDs/Ti3C2 heterostructures is also an important scientific problem. In this work, we systematically investigated the effects of an external field and novel functional groups (S, Se, Cl, Br) on the structural and electronic properties of TMDs/Ti3C2X2 heterostructures. The results revealed that the lattice parameters and interlayer distance of TMDs/Ti3C2 increased with the addition of functional groups. Both tensile and compressive strain obviously increased the interlayer distance of MoS2/Ti3C2X2 (X = S, Se, Cl, Br) and MoSe2/Ti3C2X2 (X = Se, Br). In contrast, the interlayer distance of MoSe2/Ti3C2X2 (X = S, Cl) decreased with increasing compressive strain. Furthermore, the conductivity of TMDs/Ti3C2 increased due to the addition of functional groups (Cl, Br). Strain caused the bandgap of TMDs to narrow, and effectively adjusted the electronic properties of TMDs/Ti3C2X2. At 9% compressive strain, the conductivity of MoSe2/Ti3C2Cl2 increased significantly. Meanwhile, for TMDs/Ti3C2X2, the conduction band edge (CBE) and valence band edge (VBE) at the M and K points changed linearly under an electric field. This study provides valuable insight into the combined effects of an external field and novel functional groups on the related properties of TMDs/Ti3C2X2.
RESUMEN
It's highly desired to design and fabricate an effective Z-scheme photo-catalyst with excellent charge transfer and separation, and a more negative conduction band edge (E CB) than O2/·O2 - (-0.33 eV) and a more positive valence band edge (E VB) than ·OH/OH- (+2.27 eV) which provides high-energy redox radicals. Herein, we firstly designed and synthesized a core-shell-heterojunction-structured Z-scheme system BaTiO3@In2S3 (BT@IS, labelled as BTIS) through a hydrothermal method, where commercial BT was used as the core and In(NO3)3·xH2O together with thioacetamide as the precursor of IS was utilized as the shell material. In this system, the shell IS possesses a E CB of -0.76 eV and visible-light-response E g of 1.92 eV, while the core BT possesses a E VB of 3.38 eV, which is well suited for a Z-scheme. It was found that the as-prepared BTIS possesses a higher photocatalytic degradation ability for methyl orange (MO) than commercial BT and the as-prepared IS fabricated by the same processing parameters as those of BTIS. Holes (h+) and superoxide radicals (·O2 -) were found to be the dominant active species for BTIS. In this work, the core-shell structure has inhibited the production of ·OH because the shell IS has shielded the OH- from h+. It is assumed that if the structure of BTIS is a composite, not a core-shell structure, ·OH could be produced during photocatalysis, and therefore a higher photocatalytic efficiency would be obtained. This current work opens a new pathway for designing Z-scheme photocatalysts and offers new insight into the Z-scheme mechanism for applications in the field of photocatalysis.