Bismuth-Decorated Beta Zeolites Catalysts for Highly Selective Catalytic Oxidation of Cellulose to Biomass-Derived Glycolic Acid.

Catalytic conversion of cellulose to liquid fuel and highly valuable platform chemicals remains a critical and challenging process. Here, bismuth-decorated ß zeolite catalysts (Bi/ß) were exploited for highly efficient hydrolysis and selective oxidation of cellulose to biomass-derived glycolic acid in an O2 atmosphere, which exhibited an exceptionally catalytic activity and high selectivity as well as excellent reusability. It was interestingly found that as high as 75.6% yield of glycolic acid over 2.3 wt% Bi/ß was achieved from cellulose at 180 °C for 16 h, which was superior to previously reported catalysts. Experimental results combined with characterization revealed that the synergetic effect between oxidation active sites from Bi species and surface acidity on H-ß together with appropriate total surface acidity significantly facilitated the chemoselectivity towards the production of glycolic acid in the direct, one-pot conversion of cellulose. This study will shed light on rationally designing Bi-based heterogeneous catalysts for sustainably generating glycolic acid from renewable biomass resources in the future.

Electrochemical Reduction of CO2 Toward C2 Valuables on Cu@Ag Core-Shell Tandem Catalyst with Tunable Shell Thickness.

Electrochemical CO2 reduction reaction (CO2 RR) is critical to converting CO2 to high-value multicarbon chemicals. However, the Cu-based catalysts as the only option to reduce CO2 into C2+ products suffer from poor selectivity and low activity. Tandem catalysis for CO2 reduction is an efficient strategy to overcome such problems. Here, Cu@Ag core-shell nanoparticles (NPs) with different silver layer thicknesses are fabricated to realize the tandem catalysis for CO2 conversion by producing CO on Ag shell and further achieving C-C coupling on Cu core. It is found that Cu@Ag-2 NPs with the proper thickness of Ag shell exhibit the Faradaic efficiency (FE) of total C2 products and ethylene as high as 67.6% and 32.2% at -1.1 V (versus reversible hydrogen electrode, RHE), respectively. Moreover, it exhibits remarkably electrocatalytic stability after 14 h. Based on electrochemical tests and CO adsorption capacity analyses, the origin of the enhanced catalytic performance can be attributed to the synergistic effect between Ag shell and Cu core, which strengthens the bonding strength of CO on Cu/Ag interfaces, expedites the charge transfer, increases the electrochemical surface areas (ECSAs). This report provides a Cu-based catalyst to realize efficient C2 generation via a rationally designed core-shell structured catalyst.

Efficient Simulation of Loop Quantum Gravity: A Scalable Linear-Optical Approach.

The problem of simulating complex quantum processes on classical computers gave rise to the field of quantum simulations. Quantum simulators solve problems, such as boson sampling, where classical counterparts fail. In another field of physics, the unification of general relativity and quantum theory is one of the greatest challenges of our time. One leading approach is loop quantum gravity (LQG). Here, we connect these two fields and design a linear-optical simulator such that the evolution of the optical quantum gates simulates the spin-foam amplitudes of LQG. It has been shown that computing transition amplitudes in simple quantum field theories falls into the bounded-error quantum polynomial time class, which strongly suggests that computing transition amplitudes of LQG are classically intractable. Therefore, these amplitudes are efficiently computable with universal quantum computers, which are, alas, possibly decades away. We propose here an alternative special-purpose linear-optical quantum computer that can be implemented using current technologies. This machine is capable of efficiently computing these quantities. This work opens a new way to relate quantum gravity to quantum information and will expand our understanding of the theory.