A programmable hybrid digital chemical information processor based on the Belousov-Zhabotinsky reaction.

The exponential growth of the power of modern digital computers is based upon the miniaturization of vast nanoscale arrays of electronic switches, but this will be eventually constrained by fabrication limits and power dissipation. Chemical processes have the potential to scale beyond these limits by performing computations through chemical reactions, yet the lack of well-defined programmability limits their scalability and performance. Here, we present a hybrid digitally programmable chemical array as a probabilistic computational machine that uses chemical oscillators using Belousov-Zhabotinsky reaction partitioned in interconnected cells as a computational substrate. This hybrid architecture performs efficient computation by distributing information between chemical and digital domains together with inbuilt error correction logic. The efficiency is gained by combining digital logic with probabilistic chemical logic based on nearest neighbour interactions and hysteresis effects. We demonstrated the computational capabilities of our hybrid processor by implementing one- and two-dimensional Chemical Cellular Automata demonstrating emergent dynamics of life-like entities called Chemits. Additionally, we demonstrate hybrid probabilistic logic as a viable logic for solving combinatorial optimization problems.

Facile and Reproducible Electrochemical Synthesis of the Giant Polyoxomolybdates.

Giant polyoxomolybdates are traditionally synthesized by chemical reduction of molybdate in aqueous solutions, generating complex nanostructures such as the highly symmetrical spherical {Mo102} and {Mo132}, ring-shaped {Mo154} and {Mo176}, and the gigantic protein sized {Mo368}, which combines both positive and negative curvature. These complex polyoxometalates are known to be highly sensitive to reaction conditions and are often difficult to reproduce, especially {Mo368}, which is often produced in yields far below 1%, meaning further investigation has always been limited. While the electrochemical properties of these materials have been studied, their electrochemical synthesis has not been explored. Herein, we demonstrate an alternative reliable synthetic method by means of electrochemistry. By using electrochemical synthesis, we have shown the synthesis of various reported polyoxomolybdates, along with some unreported structures with unique features that have yet to be reported by traditional synthetic methods. The six different giant polyoxomolybdates that were obtained via electrochemical synthesis range from the spherical {Mo102-xFex} and {Mo132} to the ring-shaped {Mo148} and {Mo154-x}, as well as the largest known polyoxometalate {Mo368}, with improved yield (up to 26.1% for {Mo368}), increased reproducibility, and shorter crystallization time compared to chemical reduction methods.

Electrolyte Engineering towards Efficient Water Splitting at Mild pH.

The development of processes for the conversion of H2 O and CO2 driven by electricity generated by renewable means is essential to achieving sustainable energy and chemical cycles, in which the electrocatalytic oxygen evolution reaction (OER) is one of the bottlenecks. In this study, the influences of the electrolyte molarity and identity on the OER at alkaline to neutral pH were investigated at an appreciable current density of around 10 mA cm-2 , revealing both the clear boundary of reactant switching between H2 O/OH- , owing to the diffusion limitation of OH- , and the substantial contribution of the mass transport of the buffered species in buffered mild-pH conditions. These findings suggest a strategy of electrolyte engineering: tuning the electrolyte properties to maximize the mass-transport flux. The concept is successfully demonstrated for the OER, as well as overall water electrolysis in buffered mild-pH conditions, shedding light on the development of practical solar fuel production systems.

Boosting the Performance of the Nickel Anode in the Oxygen Evolution Reaction by Simple Electrochemical Activation.

The development of cost-effective and active water-splitting electrocatalysts that work at mild pH is an essential step towards the realization of sustainable energy and material circulation in our society. Its success requires a drastic improvement in the kinetics of the anodic half-reaction of the oxygen evolution reaction (OER), which determines the overall system efficiency to a large extent. A simple electrochemical protocol has been developed to activate Ni electrodes, by which a stable NiOOH phase was formed, which could weakly bind to alkali-metal cations. The electrochemically activated (ECA) Ni electrode reached a current of 10 mA at <1.40 V vs. the reversible hydrogen electrode (RHE) at practical operation temperatures (>75 °C) and a mild pH of ca. 10 with excellent stability (>24 h), greatly surpassing that of the state-of-the-art NiFeOx electrodes under analogous conditions. Water electrolysis was demonstrated with ECA-Ni and NiMo, which required an iR-free overall voltage of only 1.44 V to reach 10 mA cmgeo-2 .