Copper-based Catalysts Research Articles

Direct Conversion of CO2 in Lime Kiln Waste Gas Catalyzed by a Copper-Based N-heterocyclic Carbene Porous Polymer.

Industrial waste gas is one of the major sources of atmospheric CO2 , yet the direct conversion of the low concentrations of CO2 in waste gases into high value-added chemicals have been a great challenge. Herein, a copper-based N-heterocyclic carbene porous polymer catalyst (Cu@NHC-1) for the direct conversion of low concentration CO2 into oxazolidinones was successfully fabricated via a facile copolymerization process followed by the complexation with Cu(OAc)2 . A continuous flow device was designed to deliver a continuous and stable carbon source for the reaction. Due to the triple synergistic effect of its porous structure, nitrogen activation sites and catalytic Cu center, Cu@NHC-1 shows highly efficient and selective adsorption, activation, and conversion of the low concentration CO2 (30 vol%). Its practical application potential is demonstrated by the ability to successfully convert the CO2 in lime kiln waste gas into oxazolidinones in satisfactory yields under mild conditions.

Highly Enhanced Chloride Adsorption Mediates Efficient Neutral CO2 Electroreduction over a Dual-Phase Copper Catalyst.

Electrocatalytic carbon dioxide reduction (CO2R) in neutral electrolytes can mitigate the energy and carbon losses caused by carbonate formation but often experiences unsatisfied multicarbon selectivity and reaction rates because of the kinetic limitation to the critical carbon monoxide (CO)-CO coupling step. Here, we describe that a dual-phase copper-based catalyst with abundant Cu(I) sites at the amorphous-nanocrystalline interfaces, which is electrochemically robust in reducing environments, can enhance chloride-specific adsorption and consequently mediate local *CO coverage for improved CO-CO coupling kinetics. Using this catalyst design strategy, we demonstrate efficient multicarbon production from CO2R in a neutral potassium chloride electrolyte (pH ∼6.6) with a high Faradaic efficiency of 81% and a partial current density of 322 milliamperes per square centimeter. This catalyst is stable after 45 h of operation at current densities relevant to commercial CO2 electrolysis (300 mA per square centimeter).

Defects Tune the Strong Metal-Support Interactions in Copper Supported on Defected Titanium Dioxide Catalysts for CO2 Reduction.

A highly active and stable Cu-based catalyst for CO2 to CO conversion was demonstrated by creating a strong metal-support interaction (SMSI) between Cu active sites and the TiO2-coated dendritic fibrous nano-silica (DFNS/TiO2) support. The DFNS/TiO2-Cu10 catalyst showed excellent catalytic performance with a CO productivity of 5350 mmol g-1 h-1 (i.e., 53,506 mmol gCu-1 h-1), surpassing that of almost all copper-based thermal catalysts, with 99.8% selectivity toward CO. Even after 200 h of reaction, the catalyst remained active. Moderate initial agglomeration and high dispersion of nanoparticles (NPs) due to SMSI made the catalysts stable. Electron energy loss spectroscopy confirmed the strong interactions between copper NPs and the TiO2 surface, supported by in situ diffuse reflectance infrared Fourier transform spectroscopy and X-ray photoelectron spectroscopy. The H2-temperature programmed reduction (TPR) study showed α, β, and γ H2-TPR signals, further confirming the presence of SMSI between Cu and TiO2. In situ Raman and UV-vis diffuse reflectance spectroscopy studies provided insights into the role of oxygen vacancies and Ti3+ centers, which were produced by hydrogen, then consumed by CO2, and then again regenerated by hydrogen. These continuous defect generation-regeneration processes during the progress of the reaction allowed long-term high catalytic activity and stability. The in situ studies and oxygen storage complete capacity indicated the key role of oxygen vacancies during catalysis. The in situ time-resolved Fourier transform infrared study provided an understanding of the formation of various reaction intermediates and their conversion to products with reaction time. Based on these observations, we have proposed a CO2 reduction mechanism, which follows a redox pathway assisted by hydrogen.

Editorial: Special Issue on “Advances on Catalysts Based on Copper”

Copper-based catalysts are very active in a wide range of different reactions, such as methanol synthesis, steam reforming/WGS, hydrogenation/dehydrogenation/transfer hydrogenation, oxidation, dehydrogenative coupling, acid-base reactions, etc [...]

Catalytic Decomposition Mechanism of PH3 on 3DCuO/C and High Value Utilization of Deactivated Catalysts.

With the widespread application of lithium iron phosphatebatteries, the production capacity of the yellow phosphorus industry has increased sharply, and the treatment of the highly toxic by-product PH3 is facing severe challenges. In this study, a 3D copper-based catalyst (3DCuO/C) that can efficiently decompose PH3 at low temperatures and low oxygen concentrations is synthesized. The PH3 capacity is up to 181.41mgg-1 , which is superior to that previously reported in the literature. Further studies indicated that the special 3D structure of 3DCuO/C induces oxygen vacancies on the surface of CuO, which is beneficial to the activation of O2 , and then promotes the adsorption and dissociation of PH3 . The doping of P after dissociation determines the formation of Cu-P, and the eventual conversion to Cu3 P leads to the deactivation of CuO active sites. More strikingly, due to the appearance of Cu3 P, the deactivated De-3DCuO/C (Cu3 P/C) exhibited significant activity in the photocatalytic degradation of rhodamine B and photocatalytic oxidation of Hg0 (gas) and can also be a candidate as an anode material for Li batteries after modification, which will provide a more thorough and economical treatment scheme for deactivated catalysts.

Efficient activation of peracetic acid for abatement of tetracycline by W-doped CuS via regulating copper redox cycling

Recently, activation of peracetic acid (PAA) with the copper-based heterogeneous catalysts has been applied for organic pollutant abatement, yet the efficiency is limited by the sluggish Cu(II)/Cu(I) redox cycling. Regarding that reductive W(IV) can continuously effectively promote the regeneration of Cu(I) via the redox-reversible W(IV)/W(VI) couple, the W(IV) component is introduced to copper sulfide for efficient activation of PAA (simplified as the W-CuS/PAA process). Morphological and structural characterizations validate the incorporation of W(IV) component into the CuS lattice structure. Under neutral conditions, tetracycline (TC) can be completely removed within 30 min with the apparent first-order rate constant 5 times higher than that of the CuS/PAA process. CH3C(=O)OO is demonstrated as the main radical responsible for TC abatement by radical quenching experiment and electron paramagnetic resonance (EPR). The redox properties and electron transfer capacity of CuS are significantly improved by the W(IV) component. The reductive W(IV) and S(–II) components facilitate the Cu(II)/Cu(I) redox cycling with the concomitant generation of reactive radicals. In addition, the influence of various parameters and coexisting anions on TC abatement is systematically investigated. Four degradation pathways of TC are put forward and the toxicity of intermediates is evaluated. The W-CuS/PAA process shows superior reuse performance and excellent adaptability in different water matrices. This study highlights the capability of the W(IV) to modulate the Cu(II)/Cu(I) redox cycle and proposes a feasible activator amelioration strategy for the efficient activation of PAA.

Comparative Study of the Effect of Hydrogen Peroxide, UV Light and Combination of both on Pharmaceutical Wastewater

Abstract: The wastewater formed in various processes in the pharmaceutical industry is considered environmentally delinquent because of its unsafe and potential for influences the aquatic ecology. Pharmaceutical wastewater comprises a high volume of organic matter, expired drugs, API, etc., that causes a lot of damage to the ecology. There are still trace quantities of suspended solids and dissolved organic material, even after secondary treatment. To advance the excellence of pharmaceutical wastewater sewage, advanced treatment is vital. Catalysts contribute extremely to the industrial revolution concerning reaction rates and a decrease in manufacturing costs. Widespread research has been recognized on numerous industrial catalyses in the previous few eras. The performance of catalysts is inclined by numerous parameters, counting synthesis approaches. In this study, a heterogenous copper-based catalyst is used which is prepared via the sol-gel method to understand its performance in the treatment of pharmaceutical wastewater. The characterization of the catalyst was done by analytical techniques. The treatment of synthetic pharmaceutical wastewater was carried out at the following operation conditions: different pH, oxidant dose (H2O2) of 1 ml – 5 ml, and the absorbance of the sample was measured using a UV spectrometer. The wavelength used was from 200nm to 1000 nm.

Enriching the Local Concentration of CO Intermediates on Cu Cavities for the Electrocatalytic Reduction of CO2 to C2+ Products

The electrochemical carbon-dioxide reduction reaction (CO2RR) to high-value multi-carbon (C2+) chemicals provides a hopeful approach to store renewable energy and close the carbon cycle. Although copper-based catalysts with a porous architecture are considered potential electrocatalysts for CO2 reduction to C2+ chemicals, challenges remain in achieving high selectivity and partial current density simultaneously for practical application. Here, the porous Cu catalysts with a cavity structure by in situ electrochemical-reducing Cu2O cavities are developed for high-performance conversion of CO2 to C2+ fuels. The as-described catalysts exhibit a high C2+ Faradaic efficiency and partial current density of 75.6 ± 1.8% and 605 ± 14 mA cm-2, respectively, at a low applied potential (-0.59 V vs RHE) in a microfluidic flow cell. Furthermore, in situ Raman tests and finite element simulation indicated that the cavity structure can enrich the local concentration of CO intermediates, thus promoting the C-C coupling process. More importantly, the C-C coupling should be major through the *CO-*CHO pathway as demonstrated by the electrochemical Raman spectra and density functional theory calculations. This work can provide ideas and insights into designing high-performance electrocatalysts for producing C2+ compounds and highlight the important effect of in situ characterization for uncovering the reaction mechanism.

The Tunable and Efficient Nanoporous CuAg Alloy Catalysts Toward Methanol Oxidation Reaction Synthesized by Electrochemical Dealloying of Metallic Glassy Precursors.

Three-dimensional (3D) nanoporous CuAg (NPCuAg) alloy catalysts with various Cu/Ag ratios are prepared by electrochemical dealloying of metallic glassy (MG) precursors. All dealloyed samples exhibit homogenous nanoporous structure and element composition distribution. After systematically evaluating their electrocatalytic performance toward MOR, it was found that the catalytic activity of the NPCuAg catalysts is enhanced along with the increase of Cu/Ag ratio, which may be attributed to the more exposed active reaction sites derived from high surface area of nanoporous structure and the optimal synergistic effect. Thus, the NPCu1.75 Ag alloy catalyst presents the best methanol electro-oxidation properties, including a high current density of 397.2 mA cm-2 and good operation stability that retaining 84.5 % catalytic activity even after 7200 s. These results outperform most reported copper-based MOR catalysts in alkaline methanol solution. Considering these advantages, the designed electrodes are expected to be promising catalysts for alkaline DMFCs applications.

A Systematic Review of Carbon Capture, Utilization and Storage: Status, Progress and Challenges

The problem of global warming and climate change has attracted global attention, and reducing the concentration of CO2 in the atmosphere is an important step towards solving the problem. This paper mainly introduces the current development status, research hotspots, challenges and some emerging technologies of carbon capture, utilization and storage (CCUS). Among CO2 capture technologies, solvent absorption technology is currently the most mature and widely used technology, among which ionic liquid technology has great application prospects because its molecular structure can be designed and different functional groups can be connected. The surface functionalization of metal–organic frameworks in the adsorption method endows them with excellent CO2 adsorption capacity. In CO2 transportation, temperature and pressure must be considered in pipeline transportation, because they will affect the phase state of CO2 transportation. The impact of impurities on CO2 pipeline transportation is a challenge that affects pipeline design and transportation safety. In CO2 utilization, the key to enhanced oil recovery, gas recovery and displacement of coalbed methane is to increase the recovery rate and increase the storage capacity at the same time. Only by strengthening the research on the adsorption behavior between CO2 and CH4 and revealing the relevant mechanism can innovative technologies be developed. The chemical utilization of CO2 has formed many routes, but they all lack certain advantages. Most scholars are working on catalysts for CO2 conversion, especially copper-based catalysts that can convert CO2 into methanol. The conversion rate of CO2 can be effectively increased through doping or process improvement. The coupling of electrocatalytic technology and renewable energy is an important development direction in the future. In CO2 storage, geological storage is currently the most important method, especially in saline aquifers. There are currently critical issues concerning reservoir integrity and leakage potential that should be further investigated. CO2 leakage will cause serious environmental problems, and the common monitoring methods are reviewed and discussed in this paper. Finally, the research status, hotspots and cooperation networks of CCUS are summarized by using CiteSpace software in order to help the development of CCUS technology. In addition, through the review and analysis, it is found that CCUS is faced with challenges such as low capture efficiency, difficulties in transformation and utilization, high operating costs, lack of strong support policies, and lack of international cooperation, which restrict the further development of CCUS.

Methanol Synthesis on Copper-Doped F Centers

We investigate the influence of single copper atoms adsorbed at F centers on the KCl (100) surface on the reaction of adsorbed hydrogen and carbon monoxide with density functional theory methods. Adsorption at an F center strongly stabilizes and reduces the copper atom, as its 4s electron pairs with the defect electron to form a closed-shell state. The Cu-doped F center readily reduces adsorbed formaldehyde and strongly interacts with carbon monoxide and methanol, weakening and activating intramolecular bonds, but unlike the empty F center, it does not dissociate methanol. During hydrogenation of adsorbed CO and CH3OH, hydrogen reacts with the adsorbed copper atom to form a stable linear HCuH complex. The hydrogen affinity of the copper atom facilitates the reaction of adsorbed molecules with hydrogen molecules as well as the attachment and removal of hydrogen atoms, enabling a fast synthesis route from carbon monoxide to methanol. The rate-limiting step of the reaction is the final hydrogenation, which recovers the active center and liberates methanol. Computing the thermodynamic and kinetic parameters of the intermediates and transition states and simulating the reaction pathway with a kinetic Monte Carlo approach, we obtained a turnover frequency of 230 s–1 per active site at 500 K and 50 bar with a 1:9 ratio of CO/H2, exceeding the rate on the empty defect by 3 orders of magnitude and the conventional catalyst by 4 orders of magnitude. The present results indicate that the addition of a metal atom to the alkali halide F center can enhance, stabilize, and control its reactivity. In the case of copper, they point toward the existence of a synthesis route for methanol with an overall activity comparable to the conventional copper-based catalysts but with much smaller metal loading.

Investigation of the Dependence of Electrocatalytic Activity of Copper and Palladium Nanoparticles on Morphology and Shape Formation

A synthesis strategy for the manufacture of inexpensive highly efficient nanostructured catalysts has been developed. The developed unique nonplatinoid copper-based catalysts with different surface morphology were investigated as a functional layer with high activity in the ethanol oxidation in alkaline media. A modifying layer with controlled morphology, composition, and excellent electrocatalytic activity was synthesized by electrochemical deposition by varying such synthesis parameters as deposition temperature and time, concentration of structure-forming additives, and electrodeposition current. The dependence of the samples’ electrocatalytic activity on the shaping factors was established. According to the electrochemical study results, the highest current density peak of up to 33.01 mA cm−2, and hence the highest catalytic activity in comparison to other samples, were possessed by a catalyst with a regular cubic particle shape. A catalyst consisting of plate-like nanoparticles with a certain percentage of disclinations had similar, but slightly less activity, with a current density peak of up to 31.59 mA cm−2. The samples’ activity values are 8 times higher for cubic particles and 7.5 times higher for particles with a triangular plate shape than for an unmodified smooth copper film. The developed samples can be considered as quite competitive to platinoid catalysts, which significantly outperform copper analogues.

Accessing the Nature of Active Sites and Particle Size Effect for Reduction of Carbon Dioxide over Copper-Based Catalysts

Although electrocatalytic conversion of CO2 (CO2ER) over bimetallic Cu-based catalysts has been regarded as a promising and compelling route for the sustainable synthesis of fuels and feedstock when combined by carbon-free electricity, questions still remain concerning the fundamental understanding of the reaction mechanism and the nature of active sites, hampering the rational design of catalyst with great activity and selectivity a priori. We report a global optimization in large scale to obtain serious realistic nanoparticles (NPs) models of different particle sizes and the identification of atom-level structures of active sites for CO products on CuZn and CuAu NPs catalysts during CO2ER, using machine learning and density functional theory calculations. After the analysis of 300 surface sites (600 computational data points) through neural network (NN) potential based high-throughput testing, we demonstrate that the bimetallic Cu-based NPs have superior CO2ER because there are many bimetallic synergistic effect sites that significantly stabilize the carboxyl intermediate during CO2 reduction to CO, breaking the inherent linear relationship. This work shed light on the structure–performance relationship over more realistic large NPs, facilitating the rational design of Cu-based catalysts in CO2ER.

Effect of the Zr/Al Molar Ratio on the Performance of Cu/ZrO2–Al2O3 Catalysts for Methanol Steam Reforming

Methanol steam reforming was widely used to produce hydrogen for fuel cells. Copper-based catalysts are popular because of its low price and high activity, whereas high selectivity to H2 is highly expected. Herein, copper-based catalysts with different Zr/Al molar ratios were prepared by the impregnation method. It was found that the 5 wt % Cu/ZrO2–8Al2O3 catalyst exhibited high activity with methanol conversion of 84.5%, hydrogen production rate of 98.7 μmol/gcat·s, and the lowest carbon monoxide selectivity of 1.5% because it had the smallest copper particle size, high medium-strong basic site, and high surface (Cu1+ + Cu0) proportion. The results of in situ FT-IR indicated that formate species might be important intermediates for H2 production.

Accurate descriptions of molecule-surface interactions in electrocatalytic CO2 reduction on the copper surfaces

Copper-based catalysts play a pivotal role in many industrial processes and hold a great promise for electrocatalytic CO2 reduction reaction into valuable chemicals and fuels. Towards the rational design of catalysts, the growing demand on theoretical study is seriously at odds with the low accuracy of the most widely used functionals of generalized gradient approximation. Here, we present results using a hybrid scheme that combines the doubly hybrid XYG3 functional and the periodic generalized gradient approximation, whose accuracy is validated against an experimental set on copper surfaces. A near chemical accuracy is established for this set, which, in turn, leads to a substantial improvement for the calculated equilibrium and onset potentials as against the experimental values for CO2 reduction to CO on Cu(111) and Cu(100) electrodes. We anticipate that the easy use of the hybrid scheme will boost the predictive power for accurate descriptions of molecule-surface interactions in heterogeneous catalysis.

Novel Copper-Based Catalytic Systems for Atom Transfer Radical Polymerization of Acrylonitrile

Atom Transfer Radical Polymerization (ATRP) is an effective catalytic process leading to well-defined polymers with desired properties. This process based on reversible deactivation of propagating chains has a lower rate in comparison with conventional radical polymerization, especially in the case of obtaining polymers with high molecular weights. Thus, the increase of the rate of this process with preserving control over molecular weight distribution is a challenging task. In this work, novel catalytic systems for Activators Generated by Electron Transfer (AGET) ATRP of acrylonitrile based on copper (II) bromide complexes were proposed. It was found that Rochelle salt (potassium sodium tartrate tetrahydrate) may be used as a reducing agent for regeneration of copper-based catalysts to increase the rate of the process. The provided UV-vis spectroscopy experiments have confirmed the reducing ability of tartaric anion. It was found that the use tandem catalytic system based on two copper complexes with different ligands also increases the polymerization rate. The performed experiments allowed us to develop a catalytic system for rapidly obtaining polyacrylonitrile polymers with desired molecular weights exceeding 100 kDa.

Synthesis, characterization, and methanol steam reforming performance of Cu/perovskite-structured catalysts

In the present work, Cu/perovskite-type structures of the general formula Cu/Ca(ZrxTi1-x)O3 (x = 1, 0.8, 0.6) were synthesized via sol-gel process and afterwards using wetness impregnation method to prepare copper-based catalysts. The physicochemical properties of the prepared catalysts were studied using XRD, SEM, NH3-TPD, H2-TPR and TGA analyses. Structural properties of the catalysts were measured through Brunauer-Emmett-Teller analysis (BET). These catalytic systems were also found to be highly active, selective and sustainable. In this regard, methanol conversion, H2 selectivity and CO selectivity were investigated and monitored by gas chromatography (GC). A high methanol conversion with a good selectivity of H2, low CO selectivity and low coke formation were achieved in steam reforming of methanol. Importantly, the morphological features of the synthesized Cu/perovskite-type porous structures contribute in improvement of catalytic activity. An obvious outcome of this study is the remarkable activity of prepared Cu/Ca(Zr0.6Ti0.4)O3 catalyst in methanol steam reforming at 300 °C due to 98.5% methanol conversion and 85.5% hydrogen selectivity.

Tuning Structures and Microenvironments of Cu-Based Catalysts for Sustainable CO2 and CO Electroreduction

ConspectusThe carbon balance has been disrupted by the widespread use of fossil fuels and subsequent excessive emissions of carbon dioxide (CO2), which has become an increasingly critical environmental challenge for human society. The production and use of renewable energy sources and/or chemicals have been proposed as important strategies to reduce emissions, of which the electrochemical CO2 (or CO) reduction reaction (CO2RR/CORR) in the aqueous systems represents a promising approach.Benefitted by the capacity of manufacturing high-value-added products (e.g., ethylene, ethanol, formic acid, etc.) with a net-zero carbon emission, copper-based CO2RR/CORR powered by sustainable electricity is regarded as a potential candidate for carbon neutrality. However, the diversity of selectivities in copper-based systems poses a great challenge to the research in this field and sets a great obstacle for future industrialization.To date, scientists have revealed that the electrocatalyst design and preparation play a significant role in achieving efficient and selective CO2-to-chemical (or CO-to-chemical) conversion. Although substantial efforts have been dedicated to the catalyst preparation and corresponding electrosynthesis of sustainable chemicals from CO2/CO so far, most of them are still derived from empirical or random searches, which are relatively inefficient and cost-intensive. Most of the mechanism studies have suggested that both intrinsic properties (such as electron states) and extrinsic environmental factors (such as surface energy) of a catalyst can significantly alter catalytic performance. Thus, these two topics are mainly discussed for copper-based catalyst developments in this Account.Here, we provided a concise and comprehensive introduction to the well-established strategies employed for the design of copper-based electrocatalysts for CO2RR/CORR. We used several examples from our research group, as well as representative studies of other research groups in this field during the recent five years, with the perspectives of tuning local electron states, regulating alloy phases, modifying interfacial coverages, and adjusting other interfacial microenvironments (e.g., molecule modification or surface energy). Finally, we employed the techno-economic assessment with a viewpoint on the future application of CO2/CO electroreduction in manufacturing sustainable chemicals. Our study indicates that when carbon price is taken into account, the electrocatalytic CO2-to-chemical conversion can be more market-competitive, and several potential value-added products including formate, methanol, ethylene, and ethanol can all make profits under optimal operating conditions. Moreover, a downstream module employing traditional chemical industrial processes (e.g., thermal polymerization, catalytic hydrolysis, or condensation process) will also make the whole electrolysis system profitable in the future. These design principles, combined with the recent advances in the development of efficient copper-based electrocatalysts, may provide a low-cost and long-lasting catalytic system for a profitable industrial-scale CO2RR in the future.

Ring-opening of furfuryl alcohol to pentanediol with hierarchically structured Cu-MFI catalysts

Metal-acid bifunctional catalysts often encounter deactivation troubles due to carbon deposition and metal agglomeration. Herein, a hierarchically porous structured Cu-MFI-AEH catalyst was developed for selective ring-opening of furfuryl alcohol to pentanediols, which exhibits >90% yield of pentanediols and improved stability. The synergistic effect of nano-copper species and Brønsted acidic protons boosts the ring opening of furfuryl alcohol. This was also disclosed by the DFT technique that small-size Cu possesses better hydrogen dissociation performance, and the introduction of ≡Si (OH) Al≡ (Brønsted acidic protons) promotes the adsorption of furfuryl alcohol and reduces the ring opening energy barrier of furfuryl alcohol. The obtained highly porous catalyst possesses a large external surface area and large pore volume, which are beneficial to offer accessible active sites and accelerate product transport, eventually resulting in superior anti-coking performance. Furthermore, the abundant silanol groups on the MFI surface produced by ammonia treatment could act as an anchoring site for grafting Cu species, resulting in strong metal-support interaction and highly anti-sintering performance. The results reported herein provide a novel strategy to improve the stability and activity of copper-based catalysts. It also inspires the conversion of biomass resources into high value-added oxygenated fine chemicals.

The Role of Copper in the Hydrogenation of Furfural and Levulinic Acid.

Currently, there is a great interest in the development of sustainable and green technologies for production of biofuels and chemicals. In this sense, much attention is being paid to lignocellulosic biomass as feedstock, as alternative to fossil-based resources, inasmuch as its fractions can be transformed into value-added chemicals. Two important platform molecules derived from lignocellulosic sugars are furfural and levulinic acid, which can be transformed into a large spectrum of chemicals, by hydrogenation, oxidation, or condensation, with applications as solvents, agrochemicals, fragrances, pharmaceuticals, among others. However, in many cases, noble metal-based catalysts, scarce and expensive, are used. Therefore, an important effort is performed to search the most abundant, readily available, and cheap transition-metal-based catalysts. Among these, copper-based catalysts have been proposed, and the present review deals with the hydrogenation of furfural and levulinic acid, with Cu-based catalysts, into several relevant chemicals: furfuryl alcohol, 2-methylfuran, and cyclopentanone from FUR, and γ-valerolactone and 2-methyltetrahydrofuran from LA. Special emphasis has been placed on catalytic processes used (gas- and liquid-phase, catalytic transfer hydrogenation), under heterogeneous catalysis. Moreover, the effect of addition of other metal to Cu-based catalysts has been considered, as well as the issue related to catalyst stability in reusing studies.