Josué M. Gonçalves

Bio: Josué M. Gonçalves is an academic researcher from University of São Paulo. The author has contributed to research in topics: Materials science & Nanoporous. The author has an hindex of 13, co-authored 56 publications receiving 541 citations.

Trimetallic oxides/hydroxides as hybrid supercapacitor electrode materials: a review

Abstract: Environmentally friendly energy sources such as solar and wind power as alternatives to fossil fuels are strategic for meeting the energy needs of an increasingly demanding population, but they are periodic or intermittent in nature, making energy storage devices fundamental for the realization of a sustainable society. Thus, the quest for much higher power and energy dense devices, especially hybrid supercapacitors, as alternatives to lithium-ion batteries, has been scaling up since the combining of the outstanding power density of supercapacitive materials with the high energy density of battery-type materials into a single device. Despite their high resistance, transition metal oxides are promising electrode materials for use in devices, since their rich electrochemistry can be activated by three main strategies to boost the specific charge capacity, charge–discharge and ion diffusion kinetics, and cyclability of devices via: (a) the incorporation of hetero-atoms that generate trimetallic oxides, (b) nanostructuration via hierarchical core@shell furry and mesoporous systems, and (c) combination with other materials to generate nanocomposites. These strategies, especially those leading to highly porous 3D core@shell architecture nanomaterials, are very successful, where trimetallic oxides, and ternary TLDHs and multicomponent systems, realized via the combination of mono- and/or bimetallic oxides and hydroxides, have demonstrated exceptionally good performances as electrode materials, presenting bright new perspectives for the future of hybrid energy storage devices.

Vanadium-containing electro and photocatalysts for the oxygen evolution reaction: a review

Abstract: The frenetic global development is improving the average quality of life in an unprecedented way, but at the expense of increasing pressure on natural resources, environmental pollution and energy demand, which are being exacerbated by population growth and industrialization in developing countries. The energy demand probably is the one contributing the most to such a situation, thus urging the development of clean and renewable alternative energy sources in order to avoid an imminent energy crisis in the near future. A possible solution is a society in which most energy needs are fulfilled by photoinduced or electrochemical water-splitting, storing solar energy as hydrogen and dioxygen gas, and releasing the chemical energy in fuel cells while regenerating water. However, the oxygen evolution reaction (OER) and the oxygen reduction reaction taking place respectively in water-splitting and fuel cells are quite sluggish because of their multielectronic and multiprotonic nature. Catalysts such as IrO2 and RuO2 are being successfully used as state-of-the-art OER electrocatalysts but such noble metal-based materials are severely limited by their scarcity and high cost. Thus, noble metal free electro/photocatalysts are being eagerly pursued to provide more sustainable alternatives. In this context, vanadium-based and vanadium-containing electro and photocatalysts based on hydroxides/oxyhydroxides/oxides, vanadates, chalcogenides and nitrides stand out among the most promising alternatives, and recent advances have demonstrated their key role in enhancing the catalytic activity by strong synergic electronic and structural effects. In fact, such high-performance materials have potential in the fabrication of fuel cells and photosynthetic devices competitive enough in converting chemical energy into electricity and solar energy into solar fuel, enabling large-scale production, storage and usage of the infinite energy of the sun in a more convenient and safe manner. Perspectives are also provided on the preparation, evaluation of synergic effects in OER electro/photocatalytic activity, and their correlation with the electronic and crystalline structure of the materials, as well as on the electrode material design.

Multifunctional spinel MnCo2O4 based materials for energy storage and conversion: a review on emerging trends, recent developments and future perspectives

Abstract: The energy requirement of modern society increases every day. The depletion of the reserves of fossil fuel combined with the deleterious effects of CO2 in the atmosphere is forcing all the world to search for alternative ways of generation and storing energy. Many scientists around the world are pursuing different forms to produce and store energy. Solar and wind sources are a reality for production of electricity, but are not continuous and require storage devices. The development of batteries and hybrid supercapacitors of high energy and power density is of great importance to complement this requirement of energy storage. Rechargeable metal–air batteries which utilize oxygen electrocatalysis seem to be an ideal choice, once the source of energy is not intermittent as solar and wind energy and is based on oxygen bifunctional electrocatalysis of both oxygen reduction and O2 evolution reactions. In addition, water splitting allows the conversion and storage of solar/wind energy into chemical energy, generating fuels with high energy content. From this perspective, spinel MnCo2O4-based materials are promising structures for energy storage and conversion of energy. In this review, the use of low cost and abundant multifunctional materials for the development of supercapacitor devices and batteries was summarized. Completely, the design of electrocatalysts for water splitting and their capability to proportionate the tetra-electronic process of the oxygen reduction reaction are reviewed, including the main strategies in the preparation of these materials and considering their key multifunctional role in the way to a more sustainable society.

Recent trends and perspectives in electrochemical sensors based on MOF-derived materials

Abstract: Metal organic frameworks (MOFs) are hybrid materials built with both organic and inorganic components. The potential of these structures was highlighted in the 1990s and since then, over 90 000 articles dealing with MOFs have been published (still growing rapidly), demonstrating a wide variety of applications. However, an improvement in the electrochemical properties of MOFs is still required to enhance the attributes to satisfy the real and strategic applications of MOF-electrode materials in energy conversion and storage (batteries, supercapacitors, and as catalysts for fuel cells and water splitting), especially in the development of electrochemical sensors. In this sense, being the focus of this review, the great potential of MOF-derived structures for the construction of electrochemical sensors is presented, highlighting the recent advances and strategies on MOF-derived materials, such as metals, metal oxide/hydroxide, metal sulfides, metal phosphides, carbons, or their composites and their potential as electrode materials. In fact, MOF-derived materials exhibit exceptional conductivity, electrochemical activity, and stability, which surpass the relative low conductivity and lack chemical/structural robustness of pristine MOFs, inheriting only the essential structural and compositional properties from their MOF precursors.

Recent advances in ternary layered double hydroxide electrocatalysts for the oxygen evolution reaction

Abstract: The high demand for energy by our society, and consequent large consumption of fossil fuel, is leading not only to its depletion but also to increasing environmental pollution, thus urging the development of clean and renewable energy sources such as based in solar energy and water in a cyclic way, by photoinduced water-splitting and regeneration in fuel cells. This means being in command of the tetra-protonic and tetra-electronic reaction mechanism of the oxygen evolution reaction, a formidable challenge that is starting to be overcome using catalysts based on more abundant and inexpensive elements. Interestingly, the most promising ones in this context are low-cost materials based on NiFe, NiCo and NiV-LDH precursors, highly flexible and tunable materials that would enable large-scale production, storage and utilization in a more convenient and safe manner. In fact, the vast majority of high performance electrocatalysts based on ternary LDHs are being produced by doping of that matrix with Co2+/3+ and V2+/3+/4+ ions to modulate the electronic and structural properties of NiFe-LDH metal sites, thus reducing the OER overpotentials while activating and increasing the concentration of active sites and improving the OER rate. On the other hand, the V ion coordination geometry can be distorted from octahedral to tetrahedral and used to induce very strong electronic effects to the neighboring transition metal ions to adjust the metal–oxygen bond energy in the transition state to the expected optimal value, and optimize the O2 release in the OER process. Finally, nanostructuration and deposition on suitable conducting materials generating nanocomposites can be used as additional strategies to enhance further the conductivity as well as the concentration and number of available active sites, while facilitating the electrolyte diffusion, thus improving their electrocatalytic performances. In short, catalysts for oxygen evolution reaction based on ternary LDHs were reviewed considering their key role in the way to a more sustainable society.

Molecular insight in structure and activity of highly efficient, low-Ir Ir-Ni oxide catalysts for electrochemical water splitting (OER)

Abstract: Mixed bimetallic oxides offer great opportunities for a systematic tuning of electrocatalytic activity and stability. Here, we demonstrate the power of this strategy using well-defined thermally prepared Ir–Ni mixed oxide thin film catalysts for the electrochemical oxygen evolution reaction (OER) under highly corrosive conditions such as in acidic proton exchange membrane (PEM) electrolyzers and photoelectrochemical cells (PEC). Variation of the Ir to Ni ratio resulted in a volcano type OER activity curve with an unprecedented 20-fold improvement in Ir mass-based activity over pure Ir oxide. In situ spectroscopic probing of metal dissolution indicated that, against common views, activity and stability are not directly anticorrelated. To uncover activity and stability controlling parameters, the Ir–Ni mixed thin oxide film catalysts were characterized by a wide array of spectroscopic, microscopic, scattering, and electrochemical techniques in conjunction with DFT theoretical computations. By means of an in...

A review on the recent advances in hybrid supercapacitors

Abstract: Presently, supercapacitors have gained an important space in energy storage modules due to their extraordinarily high power density, although they lag behind the energy density of batteries and fuel cells. This review covers recent approaches to not only increase the power density, rate capability, cyclic stability, etc. of supercapacitors, but also to increase their energy density using hybrid architectures. Electrodes are the most important component of a supercapacitor cell, and thus this review primarily deals with the design of hybrid supercapacitor electrodes offering a high specific capacitance, together with the elucidation of the mechanisms involved therein. The electrode performance significantly depends on the available surface area, porosity and conductivity of the component materials, and thus nano-structuring of the electrode is an elegant approach, which is discussed in the subsections for 0-, 1-, 2-, 3-dimensional hybrid materials, including some miscellaneous hybrids. The fabrication of different hybrid materials using metal oxides, metal sulfides, carbon materials, etc. with conducting polymers such as polyaniline and polypyrrole and their characterization are delineated from the literature data. Here, we primarily focus on the mechanism of energy storage by non-faradic electrical double-layer capacitance and faradaic pseudo-capacitance, discussing the contributions of different component mechanisms towards the total capacitance. In the hybrids, the impact of the component concentration operating via different mechanisms for charge storage on their final electrochemical performance is discussed. The specific capacitance, volumetric capacitance, charge–discharge cycles, Ragone plot, etc. of hybrid supercapacitors are described. Besides household and heavy-duty applications, the state-of-the-art future applications of supercapacitors in robotics, renewable and sustainable energy devices, wearable and self-healing supercapacitors, and biotechnology and their challenges in real-world applications with the scope of future work are elucidated.

Chemistry of Personalized Solar Energy

Abstract: Personalized energy (PE) is a transformative idea that provides a new modality for the planet’s energy future. By providing solar energy to the individual, an energy supply becomes secure and available to people of both legacy and nonlegacy worlds and minimally contributes to an increase in the anthropogenic level of carbon dioxide. Because PE will be possible only if solar energy is available 24 h a day, 7 days a week, the key enabler for solar PE is an inexpensive storage mechanism. HY (Y = halide or OH−) splitting is a fuel-forming reaction of sufficient energy density for large-scale solar storage, but the reaction relies on chemical transformations that are not understood at the most basic science level. Critical among these are multielectron transfers that are proton-coupled and involve the activation of bonds in energy-poor substrates. The chemistry of these three italicized areas is developed, and from this platform, discovery paths leading to new hydrohalic acid- and water-splitting catalysts are...

Layered double hydroxide-based electrocatalysts for the oxygen evolution reaction: identification and tailoring of active sites, and superaerophobic nanoarray electrode assembly.

Abstract: The electrocatalytic oxygen evolution reaction (OER) is a critical half-cell reaction for hydrogen production via water electrolysis. However, the practical OER suffers from sluggish kinetics and thus requires efficient electrocatalysts. Transition metal-based layered double hydroxides (LDHs) represent one of the most active classes of OER catalysts. An in-depth understanding of the activity of LDH based electrocatalysts can promote further rational design and active site regulation of high-performance electrocatalysts. In this review, the fundamental understanding of the structural characteristics of LDHs is demonstrated first, then comparisons and in-depth discussions of recent advances in LDHs as highly active OER catalysts in alkaline media are offered, which include both experimental and computational methods. On top of the active site identification and structural characterization of LDHs on an atomic scale, strategies to promote the OER activity are summarised, including doping, intercalation and defect-making. Furthermore, the concept of superaerophobicity, which has a profound impact on the performance of gas evolution electrodes, is explored to enhance LDHs and their derivatives for a large scale OER. In addition, certain operating standards for OER measurements are proposed to avoid inconsistency in evaluating the OER activity of LDHs. Finally, several key challenges in using LDHs as anode materials for large scale water splitting, such as the issue of stability and the adoption of membrane–electrode-assembly based electrolysers, are emphasized to shed light on future research directions.

Water electrolysis: from textbook knowledge to the latest scientific strategies and industrial developments

Abstract: Replacing fossil fuels with energy sources and carriers that are sustainable, environmentally benign, and affordable is amongst the most pressing challenges for future socio-economic development. To that goal, hydrogen is presumed to be the most promising energy carrier. Electrocatalytic water splitting, if driven by green electricity, would provide hydrogen with minimal CO2 footprint. The viability of water electrolysis still hinges on the availability of durable earth-abundant electrocatalyst materials and the overall process efficiency. This review spans from the fundamentals of electrocatalytically initiated water splitting to the very latest scientific findings from university and institutional research, also covering specifications and special features of the current industrial processes and those processes currently being tested in large-scale applications. Recently developed strategies are described for the optimisation and discovery of active and durable materials for electrodes that ever-increasingly harness first-principles calculations and machine learning. In addition, a technoeconomic analysis of water electrolysis is included that allows an assessment of the extent to which a large-scale implementation of water splitting can help to combat climate change. This review article is intended to cross-pollinate and strengthen efforts from fundamental understanding to technical implementation and to improve the ‘junctions’ between the field's physical chemists, materials scientists and engineers, as well as stimulate much-needed exchange among these groups on challenges encountered in the different domains.