RESUMEN
Although solar fuels photocatalysis offers the promise of converting carbon dioxide directly with sunlight as commercially scalable solutions have remained elusive over the past few decades, despite significant advancements in photocatalysis band-gap engineering and atomic site activity. The primary challenge lies not in the discovery of new catalyst materials, which are abundant, but in overcoming the bottlenecks related to material-photoreactor synergy. These factors include achieving photogeneration and charge-carrier recombination at reactive sites, utilizing high mass transfer efficiency supports, maximizing solar collection, and achieving uniform light distribution within a reactor. Addressing this multi-dimensional problem necessitates harnessing machine learning techniques to analyze real-world data from photoreactors and material properties. In this perspective, the challenges are outlined associated with each bottleneck factor, review relevant data analysis studies, and assess the requirements for developing a comprehensive solution that can unlock the full potential of solar fuels photocatalysis technology. Physics-informed machine learning (or Physics Neural Networks) may be the key to advancing this important area from disparate data towards optimal reactor solutions.
RESUMEN
Operating the dry reforming reaction photocatalytically presents an opportunity to produce commodity chemicals from two greenhouse gases, carbon dioxide and methane, however, the top-performing photocatalysts presented in the academic literature invariably rely on the use of precious metals. In this work, we demonstrate enhanced photocatalytic dry reforming performance through surface basicity modulation of a Ni-CeO2 photocatalyst by selectively phosphating the surface of the CeO2 nanorod support. An optimum phosphate content is observed, which leads to little photoactivity loss and carbon deposition over a 50-hour reaction period. The enhanced activity is attributed to the Lewis basic properties of the PO43- groups which improve CO2 adsorption and facilitate the formation of small nickel metal clusters on the support surface, as well as the mechanical stability of CePO4. A hybrid photochemical-photothermal reaction mechanism is demonstrated by analyzing the wavelength-dependent photocatalytic activities. The activities, turnover numbers, quantum efficiencies, and energy efficiencies are shown to be on par with other dry-reforming photocatalysts that use noble metals, representing a step forward in understanding how to stabilize ignoble nickel-based dry reforming photocatalysts. The challenges associated with comparing the performance of photocatalysts reported in the academic literature are also commented on.
RESUMEN
Akin to single-site homogeneous catalysis, a long sought-after goal is to achieve reaction site precision in heterogeneous catalysis for chemical control over patterns of activity, selectivity and stability. Herein, we report on metal phosphides as a class of material capable of realizing these attributes and unlock their potential in solar-driven CO2 hydrogenation. Selected as an archetype, Ni12P5 affords a structure based upon highly dispersed nickel nanoclusters integrated into a phosphorus lattice that harvest light intensely across the entire solar spectral range. Motivated by its panchromatic absorption and unique linearly bonded nickel-carbonyl-dominated reaction route, Ni12P5 is found to be a photothermal catalyst for the reverse water gas shift reaction, offering a CO production rate of 960 ± 12 mmol gcat-1 h-1, near 100% selectivity and long-term stability. Successful extension of this idea to Co2P analogs implies that metal phosphide materials are poised as a universal platform for high-rate and highly selective photothermal CO2 catalysis.
RESUMEN
The extraction and combustion of fossil natural gas, consisting primarily of methane, generates vast amounts of greenhouse gases that contribute to climate change. However, as a result of recent research efforts, "solar methane" can now be produced through the photocatalytic conversion of carbon dioxide and water to methane and oxygen. This approach could play an integral role in realizing a sustainable energy economy by closing the carbon cycle and enabling the efficient storage and transportation of intermittent solar energy within the chemical bonds of methane molecules. In this article, we explore the latest research and development activities involving the light-assisted conversion of carbon dioxide to methane.
RESUMEN
This work aims to provide an overview of producing value-added products affordably and sustainably from greenhouse gases (GHGs). Methanol (MeOH) is one such product, and is one of the most widely used chemicals, employed as a feedstock for ≈30% of industrial chemicals. The starting materials are analogous to those feeding natural processes: water, CO2, and light. Innovative technologies from this effort have global significance, as they allow GHG recycling, while providing society with a renewable carbon feedstock. Light, in the form of solar energy, assists the production process in some capacity. Various solar strategies of continually increasing technology readiness levels are compared to the commercial MeOH process, which uses a syngas feed derived from natural gas. These strategies include several key technologies, including solar-thermochemical, photochemical, and photovoltaic-electrochemical. Other solar-assisted technologies that are not yet commercial-ready are also discussed. The commercial-ready technologies are compared using a technoeconomic analysis, and the scalability of solar reactors is also discussed in the context of light-incorporating catalyst architectures and designs. Finally, how MeOH compares against other prospective products is briefly discussed, as well as the viability of the most promising solar MeOH strategy in an international context.
RESUMEN
Two-dimensional (2D) materials are of considerable interest for catalyzing the heterogeneous conversion of CO2 to synthetic fuels. In this regard, 2D siloxene nanosheets, have escaped thorough exploration, despite being composed of earth-abundant elements. Herein we demonstrate the remarkable catalytic activity, selectivity, and stability of a nickel@siloxene nanocomposite; it is found that this promising catalytic performance is highly sensitive to the location of the nickel component, being on either the interior or the exterior of adjacent siloxene nanosheets. Control over the location of nickel is achieved by employing the terminal groups of siloxene and varying the solvent used during its nucleation and growth, which ultimately determines the distinct reaction intermediates and pathways for the catalytic CO2 methanation. Significantly, a CO2 methanation rate of 100 mmol gNi-1 h-1 is achieved with over 90% selectivity when nickel resides specifically between the sheets of siloxene.