Transition Metal Aluminum Boride as a New Candidate for Ambient-Condition Electrochemical Ammonia Synthesis

Achieving more meaningful N2 conversion by reducing the energy input and carbon footprint is now being investigated through a method of N2 fixation instead of the Haber-Bosch process.Unfortunately,the electrochemical N2 reduction reaction(NRR)method as a rising approach currently still shows low selectivity(Faradaic efficiency<10%)and high-energy consumption[applied potential at least-0.2 V versus the reversible hydrogen electrode(RHE)].Here,the role of molybdenum aluminum boride single crystals,belonging to a family of ternary transition metal aluminum borides known as MAB phases,is reported for the electrochemical NRR for the first time,at a low applied potential(-0.05 V versus RHE)under ambient conditions and in alkaline media.Due to the unique nano-laminated crystal structure of the MAB phase,these inexpensive materials have been found to exhibit excellent electrocatalytic performances(NH3 yield:9.2μg h^-1cm^-2mgcat^-1.,Faradaic efficiency:30.1%)at the low overpotential,and to display a high chemical stability and sustained catalytic performance.In conjunction,further mechanism studies indicate B and Al as main-group metals show a highly selective affinity to N2 due to the strong interaction between the B 2p/Al 3p band and the N 2p orbitals,while Mo exhibits specific catalytic activity toward the subsequent reduction reaction.Overall,the MAB-phase catalyst under the synergy of the elements within ternary compound can suppress the hydrogen evolution reaction and achieve enhanced NRR performance.The significance of this work is to provide a promising candidate in the future synthesis of ammonia.

Developing More Effective Enhanced Biochar Fertilisers for Improvement of Pepper Yield and Quality

Utilization of biochar at high application rates can increase soil C and crop yields, decrease greenhouse gas emissions and reduce nutrient run-off from soils. However, the high application rate of 10 t ha-1 may not return a profit to the farmer due to the high cost of biochar. In this study biochar was modified through pre-treating the biomass and post-treating with phosphoric acid, minerals and different chemical fertilisers to study the effects of two new enhanced biochar fertilisers on the yield and quality of green pepper in a field experiment with 5 fertilisation treatments and 3 replications. The two new biochar fertilisers significantly （P 〈 0.05） increased the yield of green pepper （11.33-11.47 t ha-l）, compared with the conventional chemical fertiliser （9.72 t ha-l）. The biochar fertiliser treatments improved the vitamin C content of green pepper from 236.99 to 278.28 mg kg-1, and also significantly （P 〈 0.05） reduced the nitrate content from 132.32 to 101.92 mg kg-1, compared with chemical fertiliser. This study indicated that, compared to the use of conventional chemical fertiliser, all of the biochar fertiliser treatments could significantly improve the yield and quality of green pepper.

Effects of Enriched Biochars Containing Magnetic Iron Nanoparticles on Mycorrhizal Colonisation,Plant Growth,Nutrient Uptake and Soil Quality Improvement

At present, there is little commercial sale of biochar, since farmers find they can not gain a return on their investment in this amendment in the first few years after its application, because of the high cost associated with large application rates. To overcome this constraint, development of artificially aged enriched biochar-mineral complexes(BMCs), having a higher mineral content, surface functionality, exchangeable cations, high concentration of magnetic iron(Fe) nanoparticles, and higher water-extractable organic compounds has been undertaken by a combined team of researchers and a commercial company. Two biochars produced under different pyrolysis conditions were activated with a phosphoric acid treatment. A mixture of clay, chicken litter, and minerals were added to the biochar, and then this composite was torrefied at either 180 or 220?C. In this study a pot experiment was carried out in glasshouse conditions to determine the effects of four different BMCs, with different formulations applied at rates of 100 and 200 kg ha-1, on the mycorrhizal colonisation, wheat growth and nutrient uptake, and soil quality improvement. It was found that the phosphorus(P) and nitrogen uptake in wheat shoots were significantly greater for a low application rate of BMCs(100 kg ha-1). The present formulation of BMC was effective in enhancing growth of wheat at low application rate(100 kg ha-1). The increase in growth appeared due to an increase in P uptake in the plants that could be partly attributed to an increase in mycorrhizal colonisation and partly due to the properties of the BMC.

Feeding Biochar to Cows:An Innovative Solution for Improving Soil Fertility and Farm Productivity

Addition of biochar produced through thermal decomposition of biomass has been seen as a strategy to improve soils and to sequester carbon （C）, but wide scale implementation of the technology requires to devise innovative profitable solutions. To develop biochar utilisation with an integrated system approach, an innovative program was implemented in 2012 on a 53-ha farm in Western Australia to determine the costs and benefits of integrating biochar with animal husbandry and improvement of pastures. Biochar was mixed with molasses and fed directly to cows. The dung-biochar mixture was incorporated into the soft profile by dung beetles. We studied the changes in soil properties over 3 years. Biochar extracted from fresh dung and from the soil to a depth of 40 cm was characterised. A preliminary financial analysis of the costs and benefits of this integrated approach was also undertaken. The preliminary investigation results suggested that this strategy was effective in improving soil properties and increasing returns to the farmer. It was also concluded that the biochar adsorbed nutrients from the cow＇s gut and from the dung. Dung beetles could transport this nutrient-rich biochar into the soil profile. There was little evidence that the recalcitrant component of the biochar was reduced through reactions inside the gut or on/in the soil. Further research is required to quantify the long-term impact of integrating biochar and dung beetles into the rearing of cows.