To enhance the solar-to-chemical conversion efficiency of CO2 photocatalysis, light active materials need to be engineered into multiscale architectures that maximize photon capture and minimize optical losses. In this paper, Lourdes, Abhinav and coauthors developed a photocatalytic foam that helps achieve this goal by coating a uniform distribution and thickness indium oxide hydroxide nanorods film onto the internal surface of an oxidized nickel foam. Optimizing the size and density of pores of the photocatalytic foam enabled optimization of photochemical and thermochemical contributions to the rate for the solar reverse water gas shift. See full story at CEJ.
It remains a great challenge to overcome the intermittent and fluctuating sunlight for continuous photocatalytic fuels production. In this review, Joel and co-authors propose that persistent and memory-based photocatalysts, which efficiently operate under near zero light fluxes beyond sunset and during cloud intermittencies, are a potential solution to address and mitigate the challenge. Based on the idea of multivalent charge storage materials that allow charging during illumination and discharging to generate charge carriers upon post-illumination, this review describes examples of persistent photocatalysis systems, outlines the working mechanism, suggests strategies for performance optimization, proposes standardized Figures of Merit and discusses possible application scenes beyond solar fuels. See full story at AEM.
De-carbonizing the fossil-intensive chemicals and petrochemcials industries will help achieve a “net-zero” sustainable society. A recent report has targeted nitric acid production, an important feedstock for the production of dyes, pigments, nylon, explosives, and fertilizers. Currently, nitric acid is produced via catalytic ammonia synthesis and subsequent oxidation, but the high temperature and pressure (800-950°C, 12 atmospheres) and poor selectivity to NO lead to deleteriously high greenhouse gas CO2 and N2O emissions. In this work, a new two-step, chemical looping process has been invented which uses lattice oxygen instead of oxygen gas to oxidize NH3 to NO with increased selectivity (99.8%) and under milder reaction temperature (650 C). See full story at Advanced Science News.
Marketable, large-scale, and energy-efficient CO2 capture is essential for a net-zero future, which would be implemented at high-emitting locations, such as power plants, metal, cement, and chemical refineries. Liquid solvents such as amines, hydroxides, and organics, and metal oxide solids including alkali and alkaline earth oxides are typical absorbents, but they suffer from energy-intensive, non-selective dilemmas. How to develop an efficient material to overcome these problems remains the key challenge. Recently, the CALF-20, an intricate layered crystal composed of zinc, triazolate, and oxalate arranged in a 3D structure filled with nanometer-scale holes, has been used by Canadian company Svante in their revolutionary carbon capture process. A gram of this material has a massive surface area of 500 square meters, and the pores weakly yet preferentially bind CO2 over water. As a result, the CALF-20 displays selective CO2 physisorption at high capacities, retains it up to and beyond 40% RH with durability over 2000 h, and only requires modest amounts of energy to remove CO2. See full story at Advanced Science News.
It is with great excitement and delight that we wish to announce the Energy Materials Discovery: Enabling a Sustainable Future to be published by RSC in May, 2022 is now available for order on Amazon!
About the book: This book presents, through the eye of materials chemistry, an umbrella view of the myriad of classes of materials that make renewable energy technologies work. They are poised to facilitate the transition of non-renewable and unsustainable energy systems of the past into renewable and sustainable energy systems of the future. It is a story that often begins in chemistry laboratories with the discovery of new energy materials. Yet, to displace materials in existing energy technologies with new ones, depends not only on the ability to design and engineer a superior set of performance metrics for the material and the technology but also the requirement to meet a demanding collection of economic, regulatory, social, policy, environmental and sustainability criteria.
Artificial nitrogen reduction to ammonia is essential to life on earth, offering essential nitrogen elements for biomolecules, commodity, and fuel chemicals. The industrial Haber-Bosch process established in 1913 provides half of the fixed nitrogen in the global nitrogen cycle nowadays. However, high energy intensity, harsh reaction conditions, and extensive carbon footprint remain to be resolved. In a recent work, Lu, Yuping, and Geoff showcased an oxygen vacancy-laden tungsten oxide (WO3-x) catalyst that can facilitate electrochemical (EC) activation and fixation of the N2 molecule in thin air into ammonia in a neutral electrolyte. The EC conversion can be enabled via green electricity generated by a photovoltaic (PV) panel and the ammonia productivity can be further promoted by solar irradiation in a electrochemical cell (EC). A detailed energy and economic technical analyses demonstrate the PV-EC WO3-x system as a viable, stand-alone, modular, distributed ammonia generation system envisioned for the future green ammonia sustainable farm. See full story at Journal of Energy Chemistry.
Sunlight utilization is at the central of 21st century, being of fundamental importance to energy, environmental, climate and economy securities. However, the greatest challenge is known as the “duck curve” that depicts the mismatch between peak power demand and supply in the morning, evening and overcast days. This also applies to CO2 photocatalysis where continuous, instead of intermittent, production is favorable for potential industrial use. In the recent Nature Sustainability perspective, Dr. Loh and Prof. Ozin proposed a persistent CO2 photocatalysis scenario that could overcome the intermittent dilemma. The core idea is engineering a photocatalytic and charge-storing hybrid materials system that charges during the sunlight illumination while discharges to continue the charge carries-driven catalysis upon postillumination. In the perspective, the common strategies between catalytic engineering and charge storage engineering, various combinations of material candidates, as well as their interfacing structures are discussed in detail for CO2 hydrogenation of prolonged working period.
90% of our commodity chemicals and fuels are made from thermocatalysis industries driven by heat or grid power. In the context of carbon-neutral society, sunlight-driven photocatalysis is an ideal alternative to thermocatalysis especially for CO2 and H2O utilization. However, how to scale the lab-scale photocatalysis into real industry remains uncertain. To amplify, the efficiency of photocatalysis not only rely on the temperature related reaction rates but also the utilization of charge carriers, which requires simultaneous optimization of quantum yield and light transport. The challenges lie in photocatalyst and photoreactor engineering to use every incident photon reaching every catalytic site while minimizing parasitic absorption, reflection, scattering, transmission, and thermal conductive, convective, and radiative losses. See full story at Advanced Science News.
Professor Geoff Ozin has disseminated scientific knowledge in and beyond academe in remarkably creative ways. In addition to writing pioneering textbooks Cryochemistry, Nanochemistry and Concepts in Nanochemistry, he has written general-audience science books, including his most recent, The Story of CO2 : Big Ideas for a Small Molecule (which, in a featured interview in The Washington Post, US Energy Secretary Jennifer confirmed she was reading), with another to be published in the New Year with the Royal Society of Chemistry, 2022, Energy Materials Discovery for a Sustainable Future. He is also a constant presence in accessible science media, including the prestigious Wiley-VCH Advanced Science News– all part of his continuing leadership efforts.
Solar energy and CO2 utilizations are recognized as key to counter the global warming and build a “net-zero” sustainable society, and the surging global temperature has set the deadline of establishing revolutionary techniques in several decades. The urgency requires to assess most feasible current pathways among various solar energy and CO2 proposals and stick to it progressively. Athan Tountas, Prof. Ozin and Prof. Sain recently published their perspective ‘Solar methanol energy storage’ in the Nature Catalysis focus issue ‘CO2 Reimagined’ that acknowledges the five-year anniversary of the Paris Agreement. In it they explore the feasibility of storing renewable energy in the form of intermittent solar energy as methanol and highlight the performance and efficiency advantages of using CO-rich syngas derived from commercial-ready RWGS technology compared to direct-CO2 processes. The Focus is dedicated to progressing the fundamental science and practical implementation of this technology to advance climate goals.