25 research outputs found
Quasi-cyclic Hermitian construction of binary quantum codes
In this paper, we propose a sufficient condition for a family of 2-generator
self-orthogonal quasi-cyclic codes with respect to Hermitian inner product.
Supported in the Hermitian construction, we show algebraic constructions of
good quantum codes. 30 new binary quantum codes with good parameters improving
the best-known lower bounds on minimum distance in Grassl's code tables
\cite{Grassl:codetables} are constructed
Surface passivation for highly active, selective, stable, and scalable CO2 electroreduction
Electrochemical conversion of CO2 to formic acid using Bismuth catalysts is one the most promising pathways for industrialization. However, it is still difficult to achieve high formic acid production at wide voltage intervals and industrial current densities because the Bi catalysts are often poisoned by oxygenated species. Herein, we report a Bi3S2 nanowire-ascorbic acid hybrid catalyst that simultaneously improves formic acid selectivity, activity, and stability at high applied voltages. Specifically, a more than 95% faraday efficiency was achieved for the formate formation over a wide potential range above 1.0 V and at ampere-level current densities. The observed excellent catalytic performance was attributable to a unique reconstruction mechanism to form more defective sites while the ascorbic acid layer further stabilized the defective sites by trapping the poisoning hydroxyl groups. When used in an all-solid-state reactor system, the newly developed catalyst achieved efficient production of pure formic acid over 120 hours at 50 mA cm–2 (200 mA cell current)
New Binary Quantum Codes Constructed from Quasi-Cyclic Codes
It is well known that quantum codes can be constructed by means of classical
symplectic dual-containing codes. This paper considers a family of
two-generators quasi-cyclic codes and derives sufficient conditions for these
codes to be dual-containing. Then, a new method for constructing binary quantum
codes is proposed. As an application, we construct 11 binary quantum codes that
exceed the beak-known results. Further, another 40 new binary quantum codes are
obtained by propagation rules, all of which improve the lower bound on the
minimum distance
Heteroatom-doped Carbon Spheres from Hierarchical Hollow Covalent Organic Framework Precursors for Metal-Free Catalysis
Covalent organic frameworks (COFs) with hollow structures hold great promise for developing new types of functional materials. Herein, we report a hollow spherical COF with a hierarchical shell, which serves as an effective precursor of B,N-codoped hierarchical hollow carbon spheres. Benefiting from the synergistic effects of hierarchical porosity, high surface area, and B,N-codoping, the as-synthesized carbon spheres show prospective utility as metal-free catalysts in nitroarene reduction. A mechanistic hypothesis is proposed based on theoretical and experimental studies. Boron atoms situated meta to pyridinic Natoms are identified to be the main catalytic active sites. The anti-aromaticity originating from the codoping of B and pyridinic N atoms, not charge distribution and deformation energy, is confirmed to play a pivotal role in the catalytic reaction