The prediction of donor number and acceptor number of electrolyte solvent molecules based on machine learning

Electrolyte solvents have a critical impact on the design of high performance and safe batteries.Gutmann's donor number(DN) and acceptor number(AN) values are two important parameters to screen and design superior electrolyte solvents. However, it is more time-consuming and expensive to obtain DN and AN values through experimental measurements. Therefore, it is essential to develop a method to predict DN and AN values. This paper presented the prediction models for DN and AN based on molecular structure descriptors of solvents, using four machine learning algorithms such as Cat Boost(Categorical Boosting), GBRT(Gradient Boosting Regression Tree), RF(Random Forest) and RR(Ridge Regression).The results showed that the DN and AN prediction models based on Cat Boost algorithm possesses satisfactory prediction ability, with R^(2) values of the testing set are 0.860 and 0.96. Moreover, the study analyzed the molecular structure parameters that impact DN and AN. The results indicated that TDB02m(3D Topological distance based descriptors-lag 2 weighted by mass) had a significant effect on DN, while HATS1s(leverage-weighted autocorrelation of lag 1/weighted by I-state) plays an important role in AN. The work provided an efficient approach for accurately predicting DN and AN values, which is useful for screening and designing electrolyte solvents.

Predicting power conversion efficiency of binary organic solar cells based on Y6 acceptor by machine learning

Organic solar cells(OSCs)are a promising photovoltaic technology for practical applications.However,the design and synthesis of donor materials molecules based on traditional experimental trial-anderror methods are often complex and expensive in terms of money and time.Machine learning(ML)can effectively learn from data sets and build reliable models to predict the performance of materials with reasonable accuracy.Y6 has become the landmark high-performance OSC acceptor material.We collected the power conversion efficiency(PCE)of small molecular donors and polymer donors based on the Y6 acceptor and calculated their molecule structure descriptors.Then we used six types of algorithms to develop models and compare the predictive performance with the coefficient of determination(R^(2))and Pearson correlation coefficient(r)as the metrics.Among them,decision tree-based algorithms showed excellent predictive capability,especially the Gradient Boosting Regression Tree(GBRT)models based on small molecular donors and polymer donors exhibited that the values of R2are 0.84 and 0.69 for the testing set,respectively.Our work provides a strategy to predict PCEs rapidly,and discovers the influence of the descriptors,thereby being expected to screen high-performance donor material molecules.

Construction of BiVO4 nanosheets@WO3 arrays heterojunction photoanodes by versatile phase transformation strategy

A versatile phase transformation strategy was proposed to synthesize novel BiVO4 nanosheets(NSs)@WO3 nanorod(NR)and nanoplate(NP)arrays films.The strategy was carried out by following a three-step hydrothermal process(WO3→WO3/Bi2WO6→WO3/BiVO4).According to the characterization results,plenty of BiVO4 NSs grew well on the surface of WO3 NR and NP arrays films,thus forming the WO3/BiVO4 heterojunction structure.The prepared WO3/BiVO4 heterojunction films were used as the photoanodes for the photoelectrochemical(PEC)water splitting.As indicated by the results,the photoanodes exhibited an excellent PEC activity.The photocurrent densities of the WO3/BiVO4 NR and NP photoanodes at 1.23 V(vs RHE)without cocatalyst under visible light illumination reached up to about 1.56 and 1.20 mA/cm2,respectively.

Preparation and evaluation of bis(diallyl alkyl tertiary ammonium salt) polymer as a promising adsorbent for phosphorus removal

Problems associated with water eutrophication due to high phosphorus concentrations and related environmentally safe solutions have attracted wide attention.A novel bis(diallyl alkyl tertiary ammonium salt)polymer,particularly poly(N1,N1,N6,N6-tetraallylhexane-1,6-diammonium dichloride)(PTAHDADC),was synthesized and characterized by Fourier transform infrared spectroscopy,nuclear magnetic resonance,scanning electron microscopy,mercury intrusion method,and thermogravimetric analysis.The adsorption characteristics in phosphorus were evaluated in dilute solution,and the recycling properties of PTAHDADC were investigated.Results showed that PTAHDADC possessed macropores with a size distribution ranging from 30 to 130μm concentrating at 63μm in diameter and had 46.52%of porosity,excellent thermal stability below 530 K,and insolubility.PTAHDADC could effectively remove phosphorus at p H=7–11 and had a removal efficiency exceeding 98.4%at pH=10–11.The adsorption equilibrium data of PTAHDADC for phosphorus accorded well with the Langmuir and pseudo-second-order kinetic models.Maximum adsorption capacity was 52.82 mg/g at 293 K.PTAHDADC adsorbed phosphorus rapidly and reached equilibrium within 90 min.Calculated activation energy Eawas 15.18 k J/mol.PTAHDADC presented an excellent recyclability with only 8.23%loss of removal efficiency after five adsorption–desorption cycles.The morphology and structure of PTAHDADC slightly changed as evidenced by the pre-and post-adsorption of phosphorus,but the process was accompanied by the partial deprotonation of the(–CH2)3-NH+group of PTAHDADC.The adsorption was a spontaneous exothermic process driven by entropy through physisorption,electrostatic attraction,and ion exchange.Survey results showed that PTAHDADC was a highly efficient and fast-adsorbing phosphorus-removal material prospective in treating wastewater.

A chemically stable nanoporous coordination polymer with fixed and free Cu^(2+)ions for boosted C_(2)H_(2)/CO_(2)separation

Safely and highly selective acetylene(C_(2)H_(2))capture is a great challenge,because of its highly explosive nature,as well as its nearly similar molecule size and boiling point toward the main impurity of carbon dioxide(CO_(2)).Adsorption separation has shown a promising future.Herein,a new nanoporous coordination polymer(PCP)adsorbent with fixed and free Cu ions(termed NTU-66-Cu)was prepared through post-synthetic approach via cation exchanging from the pristine NTU-66,an anionic framework with new 3,4,6-c topology and two kinds of cages.The NTU-66-Cu shows significantly improved C_(2)H_(2)/CO_(2)selectivity from 6 to 32(v/v:1/1)or 4 to 4_(2)(v/v:1/4)at low pressure under 298 K,along with enhanced C_(2)H_(2)capacity(from 89.22to 111.53 cm^(3)·g^(-1)).More importantly,this observation was further validated by density functional theory(DFT)calculations and breakthrough experiments under continuous and dynamic conditions.Further,the excellent chemical stability enables this adsorbent to achieve recycle C_(2)H_(2)/CO_(2)separation without loss of C_(2)H_(2)capacity.