Mechanochemical approaches to chemical synthesis offer the promise of improved yields, new reaction pathways and greener syntheses. Scaling these syntheses is a crucial step toward realizing a commercially viable process. Although much work has been performed on laboratory-scale investigations little has been done to move these approaches toward industrially relevant scales. Moving reactions from shaker-type mills and planetary-type mills to scalable solutions can present a challenge. We have investigated scalability through discrete element models, thermal monitoring and reactor design. We have found that impact forces and macroscopic mixing are important factors in implementing a truly scalable process. These observations have allowed us to scale reactions from a few grams to several hundred grams and we have successfully implemented scalable solutions for the mechanocatalytic conversion of cellulose to value-added compounds and the synthesis of edge functionalized graphene.

The hydrogenation of waste gas carbon dioxide into value added molecules could reduce greenhouse gas emissions and our dependence on nonrenewable energy sources. Catalytic paths toward this goal typically involve high pressures and low abundance transition metal catalysts. Here, we have found that vacancies induced in defect-laden hexagonal boron nitride (dh-BN) can effectively activate the CO 2 molecule for hydrogenation. Subsequent hydrogenation to formic acid (HCOOH) and methanol (CH 3 OH) occur through vacancy facilitated coadsorption of hydrogen and CO 2 . More importantly, we find that dh-BN catalyzes formic acid formation observable at reaction temperatures above 160 °C and pressures of 583 kPa, while methanol formation is observed at lower temperatures (as low as 20 °C). Methanol formation occurs with a TOF of 1.52 × 10 −2 s −1 and TON of 289 at 20 °C. Carbon dioxide (CO 2 ) is a major greenhouse gas and the main component of all combustion products produced in power generation and transportation. In addition, boron and nitrogen are abundant elements and thus, catalysts prepared from h-BN would allow catalytic recovery of value-added molecules facilitating efforts to reduce the emissions of this gas.

The use of hexagonal boron nitride (h-BN) as a non-metal heterogeneous catalyst has been a popular subject in research since the discovery of its catalytic properties in 2016. Previous work found that an activation step was necessary for producing an effective catalyst. Density functional theory (DFT) calculations indicate defect sites, such as nitrogen (V N ) and boron (V B ) vacancies, bind favourably to olefins, hydrogen, and oxygen. In particular, the visible fluorescence intensity of processed h-BN increased with the length of exposure to air. The fluorescence behaviour of dh-BN powders when exposed to air after exposure to species such as argon, propene, and carbon dioxide is presented. Density of state calculations for molecular and atomic oxygen bound to V N and V B show that this increase in fluorescence may be due to atomic oxygen binding to V N . The fluorescence emission behaviour observed in dh-BN powders and its relationship to DOS of oxygen species bound to catalytically active defect sites provides a better understanding of potential deactivation modes for catalysts based on dh-BN.

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