Alkoxide Species Research Articles

The Operando Nature of Isobutene Adsorbed in Zeolite H−SSZ−13 Unraveled by Machine Learning Potentials Beyond DFT Accuracy

AbstractUnraveling the nature of adsorbed olefins in zeolites is crucial to understand numerous zeolite‐catalyzed processes. A well‐grounded theoretical description critically depends on both an accurate determination of the potential energy surface (PES) and a reliable account of entropic effects at operating conditions. Herein, we propose a transfer learning approach to perform random phase approximation (RPA) quality enhanced sampling molecular dynamics simulations, thereby approaching chemical accuracy on both the determination and exploration of the PES. The proposed methodology is used to investigate isobutene adsorption in H−SSZ−13 as prototypical system to estimate the relative stability of physisorbed olefins, carbenium ions and surface alkoxide species (SAS) in Brønsted‐acidic zeolites. We show that the tert‐butyl carbenium ion formation is highly endothermic and no entropic stabilization is observed compared to the physisorbed complex within H−SSZ−13. Hence, its predicted concentration and lifetime are negligible, making a direct experimental observation unlikely. Yet, it remains a shallow minimum on the free energy surface over the whole considered temperature range (273–873 K), being therefore a short‐lived reaction intermediate rather than a transition state species.

The Operando Nature of Isobutene Adsorbed in Zeolite H-SSZ-13 Unraveled by Machine Learning Potentials Beyond DFT Accuracy.

Unraveling the nature of adsorbed olefins in zeolites is crucial to understand numerous zeolite-catalyzed processes. A well-grounded theoretical description critically depends on both an accurate determination of the potential energy surface (PES) and a reliable account of entropic effects at operating conditions. Herein, we propose a transfer learning approach to perform random phase approximation (RPA) quality enhanced sampling molecular dynamics simulations, thereby approaching chemical accuracy on both the determination and exploration of the PES. The proposed methodology is used to investigate isobutene adsorption in H-SSZ-13 as prototypical system to estimate the relative stability of physisorbed olefins, carbenium ions and surface alkoxide species (SAS) in Brönsted-acidic zeolites. We show that the tert-butyl carbenium ion formation is highly endothermic and no entropic stabilization is observed compared to the physisorbed complex within H-SSZ-13. Hence, its predicted concentration and lifetime are negligible, making a direct experimental observation unlikely. Yet, it remains a shallow minimum on the free energy surface over the whole considered temperature range (273--873 K), being therefore a short-lived reaction intermediate rather than a transition state species.

The Operation Window of Lithium Iron Phosphate/Graphite Cells Affects their Lifetime

Lithium iron phosphate (LFP) battery cells are ubiquitous in electric vehicles and stationary energy storage because they are cheap and have a long lifetime. This work compares LFP/graphite pouch cells undergoing charge-discharge cycles over five state of charge (SOC) windows (0%–25%, 0%–60%, 0%–80%, 0%–100%, and 75%–100%). Cycling LFP cells across a lower average SOC results in less capacity fade than cycling across a higher average SOC, regardless of depth of discharge. The primary capacity fade mechanism is lithium inventory loss due to: lithiated graphite reactivity with electrolyte, which increases incrementally with SOC, and lithium alkoxide species causing iron dissolution and deposition on the negative electrode at high SOC which further accelerates lithium inventory loss. Our results show that even low voltage LFP systems (3.65 V) have a tradeoff between average SOC and lifetime. Operating LFP cells at lower average SOC can extend their lifetime substantially in both EV and grid storage applications.

Cationic Bis(hydrosilane)-Coinage-Metal Complexes: Synthesis, Characterization, and Use as Catalysts for Outer-Sphere C=O Hydrosilylation Not Involving Metal Hydrides.

The preparation of cationic bis(hydrosilane)-coinage-metal complexes by chloride abstraction from the neutral metal chloride precursors with Na[BArF 4] is described. Unlike previously reported hydrosilane-stabilized copper and silver complexes, the presented complexes are cationic and feature two bidentate (ortho-silylphenyl)phosphine ligands. These complexes were fully characterized by NMR spectroscopy and X-ray diffraction analysis, revealing that both Si-H bonds are activated by the Lewis acidic cationic metal center. The new complexes were found to be effective in catalytic carbonyl hydrosilylation, leading to the corresponding silyl ethers under mild conditions without the addition of an external base. Combined mechanistic control experiments and quantum chemical calculations support an ionic outer-sphere mechanism, in which a neutral metal alkoxide species instead of a metal hydride is the key intermediate that interacts with the silylcarboxonium ion to generate the silyl ether.

Cationic Bis(hydrosilane)−Coinage Metal Complexes: Synthesis, Characterization, and Use as Catalysts for Outer‐Sphere C=O Hydrosilylation Not Involving Metal Hydrides

The preparation of cationic bis(hydrosilane)–coinage‐metal complexes by chloride abstraction from the neutral metal chloride precursors with Na[BArF4] is described. Unlike previously reported hydrosilane‐stabilized copper and silver complexes, the presented complexes are cationic and feature two bidentate ortho‐(silylphenyl)phosphine ligands. These complexes were fully characterized by NMR spectroscopy and X‐ray diffraction analysis, revealing that both Si–H bonds are activated by the Lewis acidic cationic metal center. The new complexes were found to be effective in catalytic carbonyl hydrosilylation, leading to the corresponding silyl ethers under mild conditions without the addition of an external base. Combined mechanistic control experiments and quantum chemical calculations support an ionic outer‐sphere mechanism, in which a neutral metal alkoxide species instead of a metal hydride is the key intermediate that interacts with the silylcarboxonium ion to generate the silyl ether.

A Powerful Strategy for Synthesizing Block Copolymers via Bimetallic Synergistic Catalysis.

Block copolymers, comprising polyether and polyolefin segments, are an important and promising category of functional materials. However, the lack of efficient strategies for the construction of polyether-b-polyolefin block copolymers have hindered the development of these materials. Herein, we propose a simple and efficient method to obtain various block copolymers through the copolymerization of epoxides and acrylates via bimetallic synergistic catalysis. The copolymerization of epoxides and acrylates proceeds in a sequence-controlled manner, where the epoxides-involved homo- or copolymerization occurs first, followed by the homopolymerization of acrylates initiated by the alkoxide species from the propagating polymer chain, thus yielding copolymers with a block structure. Notably, the high monomer compatibility of this powerful strategy provides a platform for synthesizing various polyacrylate-based block copolymers comprising polyether, polycarbonate, polythiocarbonate, polyester, and polyurethane segments, respectively.

A Powerful Strategy for Synthesizing Block Copolymers via Bimetallic Synergistic Catalysis

AbstractBlock copolymers, comprising polyether and polyolefin segments, are an important and promising category of functional materials. However, the lack of efficient strategies for the construction of polyether‐b‐polyolefin block copolymers have hindered the development of these materials. Herein, we propose a simple and efficient method to obtain various block copolymers through the copolymerization of epoxides and acrylates via bimetallic synergistic catalysis. The copolymerization of epoxides and acrylates proceeds in a sequence‐controlled manner, where the epoxides‐involved homo‐ or copolymerization occurs first, followed by the homopolymerization of acrylates initiated by the alkoxide species from the propagating polymer chain, thus yielding copolymers with a block structure. Notably, the high monomer compatibility of this powerful strategy provides a platform for synthesizing various polyacrylate‐based block copolymers comprising polyether, polycarbonate, polythiocarbonate, polyester, and polyurethane segments, respectively.

Mononuclear Uranium and Heterobimetallic Actinide (An=Th, U) Alkoxides with Divalent Group 14 Elements (MII=Ge, Sn, Pb)

AbstractWhen compared to main group and lanthanide elements, the heterobimetallic alkoxides of actinide elements with metals other than alkali metals are elusive. We report here for the first time alkoxide derivatives containing early actinides and the divalent group 14 elements. For this purpose in this work, co‐alcoholysis reactions of silyl amides of divalent group 14 elements (MII=Ge, Sn, Pb) and actinides (AnIV=Th, U) were studied that resulted in the formation of [AnM(OtBu)6] (1‐AnM) (AnIV=Th, MII=Ge, Sn, Pb; AnIV=U, MII=Ge, Sn). A 2‐electron redox reaction occurred in the UIV‐PbII couple, which generated nearly quantitatively a UV alkoxide species and elemental lead. Precise adjustments of the stoichiometry in this reaction allowed to synthesize [U(OtBu)5Py] (3), amongst others in high yield. 3 and the UIV alkoxide [U(OtBu)4(Py)2] (4) described in this work represent first mononuclear UIV or UV containing alkoxides. First promising attempts to use [U(OtBu)5Py] (3) as a starting material in co‐alcoholysis reactions with divalent group 14 silylamides resulted in the formation of heterobimetallic UV‐MII alkoxides [UM(OtBu)7] (MII=Ge, Sn, Pb) amongst others. All compounds described in this study were thoroughly characterized by multi‐nuclear NMR and IR spectroscopic investigations, single crystal X‐ray diffraction data, and CHN‐ analysis.

Construction of HfO2 nanoparticles with rich hydroxyl group for the efficient catalytic transfer hydrogenation of furfural

Although metal oxide has unique advantages in catalytic transfer hydrogenation (CTH) of furfural (FAL) into furfuryl alcohol (FOL), the excessive stability of the metal site and oxygen coordination leads to the inert Lewis acid site in the oxide, which affects the catalytic activity and limits its broader application. It is known that the hydroxyl group on the oxide surface can promote the adsorption of isopropanol in an alkoxide species by assisting its deprotonation, thereby activating the metal site and enhance the overall reaction activity. However, constructing metal oxide with rich hydroxyl groups is always challenging. This contribution prepared a series of HfO2 nanoparticles (NPs) with rich hydroxyl groups through hydrothermal methods. Systematic characterizations proved the presence of hydroxyl groups on the surface of HfO2 NPs, which promoted its adsorption capacity for isopropanol (hydrogen donor and reaction solvent) and substrate (FAL), thus accelerating the subsequent reaction for CTH of FAL into FOL. As a result, a 100% of FAL conversion with 95.2% of FOL yield was obtained at 160 °C in 4 h, which has significant advantages over commercial and other literature reported oxides. This finding provides a new idea for designing of efficient metal oxides for the CTH reaction by enhancing the hydroxyl group.

Alkoxide-Decorated Copper Nanoparticles on Amidine-Modified Polymers as Hydrogenation Catalysts for Enabling H2 Heterolysis

Direct formation of Cu nanoparticles was accomplished on an amidine- and guanidine-functionalized polymer (polystyrene-bound 1,8-diazabicyclo[5.4.0]undec-7-ene (PS-DBU) and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (PS-TBD), respectively) by thermal treatment of Cu(acac)2 (acac = acetylacetonato) in methanol under pressurized H2. The immobilized structure was characterized by inductively coupled plasma atomic emission spectroscopy (ICP-AES), elemental analysis, and microscopic analysis. X-ray photoelectron spectroscopy (XPS) data indicated that the nanoparticles consisted of Cu(0) and oxygenated Cu(I). The Cu(0)/Cu(I) ratio was determined by X-ray absorption spectroscopy. In particular, X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) studies indicated the inclusion of alkoxides bound to Cu nanoparticles. Further 13C-labeled experiments allowed us to identify the Cu methoxide species by solid-state 13C nuclear magnetic resonance (NMR). A series of alkoxide-incorporated Cu nanoparticles were proven to facilitate H2 heterolysis and were applied in the catalytic hydrogenation of CO2 to formate salts in the presence of a nitrogen base. The catalytic activity increased with decreased mean particle size and increased Cu(I) content, indicating that the Cu(I) alkoxide species played an indispensable role in hydrogenation. The combination of Cu/PS-DBU and 2-tert-butyl-1,1,3,3-tetramethylguanidine (BTMG) achieved a maximum turnover number of 2450 at 100 °C without leaching or aggregation of the nanosized catalysts.

The Pseudomonas aeruginosa PAO1 metallo flavoprotein d-2-hydroxyglutarate dehydrogenase requires Zn2+ for substrate orientation and activation

Pseudomonas aeruginosa PAO1 d-2-hydroxyglutarate (D2HG) dehydrogenase (PaD2HGDH) oxidizes D2HG to 2-ketoglutarate during the vital l-serine biosynthesis and is a potential therapeutic target against P.aeruginosa. PaD2HGDH, which oxidizes d-malate as an alternative substrate, has been demonstrated to be a metallo flavoprotein that requires Zn2+ for activity. However, the role of Zn2+ in the enzyme has not been elucidated, making it difficult to rationalize why nature employs both a redox center and a metal ion for catalysis in PaD2HGDH and other metallo flavoenzymes. In this study, recombinant His-tagged PaD2HGDH was purified to high levels in the presence of Zn2+ or Co2+ to investigate the metal's role in catalysis. We found that the flavin reduction step was reversible and partially rate limiting for the enzyme's turnover at pH 7.4 with either D2HG or d-malate with similar rate constants for both substrates, irrespective of whether Zn2+ or Co2+ was bound to the enzyme. The steady-state pL profiles of the kcat and kcat/Km values with d-malate demonstrate that Zn2+ mediates the activation of water coordinated to the metal. Our data are consistent with a dual role for the metal, which orients the hydroxy acid substrate in the enzyme's active site and rapidly deprotonates the substrate to yield an alkoxide species for hydride transfer to the flavin. Thus, we propose a catalytic mechanism for PaD2HGDH oxidation that establishes Zn2+ as a cofactor required for substrate orientation and activation during enzymatic turnover.

Mechanistic Studies of Carbonyl Allylation Mediated by (NHC)CuH: Isoprene Insertion, Allylation, and β-Hydride Elimination.

The ability of Cu-H complexes to undergo selective insertion of unsaturated hydrocarbons under mild conditions has rendered them valuable, versatile catalysts. The direct formation of Cu allyl intermediates from unfunctionalized 1,3-dienes and transient Cu hydrides is an appealing strategy for upgrading conjugated diene feedstocks. However, empirical mechanistic studies of the underlying elementary steps and characterization of key intermediates in Cu-H catalysis are sparse. Using [(NHC)CuH]2 (NHC = N-heterocyclic carbene), we examined the steric effects of NHC ligands on two key elementary steps of CuH-catalyzed carbonyl allylation: the insertion of a diene into the Cu-H bond to produce a Cu-allyl complex, and the formation of C-C bonds from stoichiometric allylations of ketones and aldehydes. The resulting allyl and homoallylic alkoxide complexes have been characterized by NMR spectroscopy and single-crystal X-ray diffraction. Employing isolable (NHC)Cu-allyl complexes, we further evaluated the roles of the ligand size, electronic properties of carbonyl substrates, coordinating groups within the substrate, and solvent on the regioselectivity, diastereoselectivity, and relative rate of the C-C bond formation step. In contrast to the clean allylation of ketones, allylation of aldehydes provided a rare example of a formal β-hydride elimination reaction from a secondary homoallylic alkoxide species. Mechanistic studies of key elementary steps provide insights for a range of catalytic reactions of dienes mediated by hydride complexes.

A Stereodivergent–Convergent Chiral Induction Mode in Atroposelective Access to Biaryls via Rhodium-Catalyzed C–H Bond Activation

Understanding the reaction mechanisms, particularly the chiral induction mode, is critical for the development of new asymmetric catalytic reactions. Rhodium(III)-catalyzed C–H activation en route to atroposelective [4 + 2] annulative coupling with α-diazo β-ketoesters has been realized, affording axially chiral phenanthrenes in good to excellent enantioselectivity. A combination of experimental and computational studies revealed a nontraditional stereodivergent–convergent chiral induction mode. The reaction proceeded with a rhodafluorene intermediate, followed by competitive, constructive, and stereodivergent migratory insertions of the two Rh–C(aryl) bonds into the carbene species to give β-ketoester intermediates. Then, the other Rh–C(aryl) bond migratorily inserts into the ketone carbonyl group. Following this stereodetermining carbonyl insertion, an ester-chelated rhodium(III) alkoxide species bearing two poorly controlled chiral centers and a well-controlled C(sp2)–C(sp3) chiral axis is generated. The final product is delivered via stereoconvergent elimination of a rhodium(III) species with retention of the well-controlled axial chirality and with loss of the central chirality.

Copper-Catalyzed Ligand-Controlled Selective Borocarbonylation of α-Substituted Styrenes Toward β-Boryl Aldehydes and Cyclopropyl Boronate Esters

Copper-Catalyzed Ligand-Controlled Selective Borocarbonylation of α-Substituted Styrenes Toward β-Boryl Aldehydes and Cyclopropyl Boronate Esters

Investigation into the Enhanced Catalytic Oxidation of o-Xylene over MOF-Derived Co3O4 with Different Shapes: The Role of Surface Twofold-Coordinate Lattice Oxygen (O2f)

In the removal of volatile organic compounds (VOCs), Co3O4 catalysts with various morphologies are highly efficient due to rich active sites such as Co3+, adsorbed oxygen, and surface lattice oxygen species. It is worthwhile further disclosing the crucial roles and reaction mechanism of these active sites. The facile and uniform metal–organic framework (MOF) derivation method was selected to synthesize Co3O4 catalysts with different shapes for the catalytic oxidation of o-xylene: rod-like Co3O4-R exhibited a lower T90% of 270 °C, superior stability, and water resistance compared with spherical Co3O4-S. The enhanced catalytic performance of Co3O4-R probably originated from its more active surface lattice oxygen, namely, twofold-coordinate lattice oxygen (O2f), on exposed (220) planes, which gave rise to larger CO2 generation as revealed by HR-TEM, O2-TPD, and o-xylene-TPD. In situ DRIFTS study also showed that Co3O4-R adsorbed and oxidized more o-xylene via surface O2f, forming intermediates including alkoxide, carboxylate, and anhydride species and leaving oxygen vacancy. After the introduction of gaseous oxygen, the disappearance of intermediates occurred more rapidly on Co3O4-R owing to the good oxygen mobility. The lower formation energy of oxygen vacancy (EOv, 2.61 eV) and higher adsorption energy of oxygen (Eads,O2, −1.71 eV) on Co3O4-R theoretically confirmed the easier oxygen vacancy formation and gaseous oxygen replenishment on Co3O4-R due to the existence of active O2f on the surface. Therefore, the role of surface O2f in oxygen vacancy formation and gaseous oxygen replenishment crucially contributed to the enhanced catalytic oxidation of o-xylene over MOF-derived Co3O4 catalysts with different shapes. This study might shed light on the thorough understanding of active oxygen species in VOC catalytic oxidation and the preparation of efficient catalysts with various morphologies.

Effect of Fluoroethylene Carbonate Additives on the Initial Formation of the Solid Electrolyte Interphase on an Oxygen-Functionalized Graphitic Anode in Lithium-Ion Batteries.

The formation of a solid electrolyte interphase (SEI) at the electrode/electrolyte interface substantially affects the stability and lifetime of lithium-ion batteries (LIBs). One of the methods to improve the lifetime of LIBs is by the inclusion of additive molecules to stabilize the SEI. To understand the effect of additive molecules on the initial stage of SEI formation, we compare the decomposition and oligomerization reactions of a fluoroethylene carbonate (FEC) additive on a range of oxygen-functionalized graphitic anodes to those of an ethylene carbonate (EC) organic electrolyte. A series of density functional theory (DFT) calculations augmented by ab initio molecular dynamics (AIMD) simulations reveal that EC decomposition on an oxygen-functionalized graphitic (112̅0) edge facet through a nucleophilic attack on an ethylene carbon site (CE) of an EC molecule (S2 mechanism) is spontaneous during the initial charging process of LIBs. However, decomposition of EC through a nucleophilic attack on a carbonyl carbon (CC) site (S1 mechanism) results in alkoxide species regeneration that is responsible for continual oligomerization along the graphitic surface. In contrast, FEC prefers to decompose through an S1 pathway, which does not promote alkoxide regeneration. Including FEC as an additive is thus able to suppress alkoxide regeneration and results in a smaller and thinner SEI layer that is more flexible toward lithium intercalation during the charging/discharging process. In addition, we find that the presence of different oxygen functional groups at the surface of graphite dictates the oligomerization products and the LiF formation mechanism in the SEI.

CeCoOx-MNS catalyst derived from three-dimensional mesh nanosheet Co-based metal–organic frameworks for highly efficient catalytic combustion of VOCs

Various three-dimensional (3D) Co-based metal organic frameworks (Co-MOFs) are successfully synthesized through modulation and reconstruction of secondary building units (SBU) with Co ions, including three-dimensional nanocube Co-MOFs (Co-MOFs-NC), three-dimensional mesh nanosheets Co-MOFs (Co-MOFs-MNS) and three-dimensional prismatic nanotube Co-MOFs (Co-MOFs-PNT). Specifically, mesh nanosheets Co-MOFs-MNS and prismatic nanotube Co-MOFs-PNT are synthesized for the first time through a post-processing strategy of nanocubic Co-MOFs-NC. It is discovered that the CeCoOx-MNS catalyst derived from Co-MOFs-MNS precursor following wet impregnation of cerium ions exhibits a superior activity for the complete oxidation of benzene, toluene and δ-xylene. Through a series of characterizations, it is verified that the CeCoOx-MNS catalyst owns more Co3+ and Ce3+ species, excellent redox performance (Ce4++Co2+→Ce3++Co3+), and abundant surface weak acid sites, which promote jointly the conversion of VOCs at a lower temperature. More importantly, in situ DRIFTS results over CeCoOx catalyst verify that the alkoxide, benzoate and anhydride species are the main intermediates, indicating that reaction pathway is likely to be as follows: adsorbed toluene → benzyl alcohol → benzoate → anhydride → acetate→ …→ CO2 and H2O.

Steric Effects of HN(CH2CH2PR2)2 on the Nuclearity of Copper Hydrides

Copper hydride clusters of the type (RPNHP)nCu2nH2n (RPNHP = HN(CH2CH2PR2)2; n = 2 and 3) have been synthesized from the reaction of (RPNHP)CuBr with KOtBu under H2 or in one pot from a 1:2:2 mixture of RPNHP, CuBr, and KOtBu under H2. With medium-sized phosphorus substituents (R = iPr and Cy), the phosphine ligands stabilize both hexanuclear and tetranuclear clusters; however, the smaller clusters are kinetic products and aggregate further over time. Use of a bulkier ligand tBuPNHP leads to the formation of only a tetranuclear cluster. Crystallographic studies reveal a distorted octahedral Cu6 unit in (iPrPNHP)3Cu6H6 (2a) and (CyPNHP)3Cu6H6 (2b), while a tetrahedral Cu4 unit exists in (CyPNHP)2Cu4H4 (2b') and (tBuPNHP)2Cu4H4 (2c'), all furnished with face-capping hydrides and bridging RPNHP ligands. The aggregations are maintained in solution, although hydrides are fluxional. These copper clusters are capable of reducing aldehydes and ketones to the corresponding copper alkoxide species. Ranking their reactivity toward N-methyl-2-pyrrolecarboxaldehyde gives 2b' > 2a, 2b ≫ 2c', which correlates inversely with the order of thermal stability (against decomposition and cluster expansion).

Toluene oxidation over monolithic MnOx/La-Al2O3 catalyst prepared by a CTAB-assisted impregnation method

The monolithic MnOx/La-Al2O3 catalyst (Mn/La-Al-CTAB) prepared by CTAB (cetyl trimethyl ammonium bromide)-assisted impregnation method was used for the oxidation of toluene, and an improved catalytic performance (TOF = 4.76, T90% = 273 °C) was achieved in comparison with the reference (Mn/La-Al) (TOF = 2.34, T90% = 295 °C). The physicochemical properties of the catalyst were investigated through XRD, Raman spectra, TEM, BET, H2-TPR, O2-TPD, XPS and DRIFT spectra. It is confirmed that Mn/La-Al-CTAB possesses higher dispersion and smaller crystalline size of MnOx species as well as higher concentrations of Mn3+ and lattice oxygen. Thus, it exhibits better reducibility and oxygen mobility, which is a key factor to result in an increased catalytic activity. Moreover, DRIFT spectra indicate that the intermediates such as alkoxide species, benzaldehyde, benzoate and maleic anhydride more easily form on the surface of Mn/La-Al-CTAB, this is an important reason for the enhanced toluene oxidation.

Green and Functional Aerogels by Macromolecular and Textural Engineering of Chitosan Microspheres.

Tremendous interest was recently devoted to the preparation of porous and functional materials through sustainable route, including primarily the use of renewable biopolymers instead of petroleum-sourced synthetic chemicals. Among the biopolymers available in enormous quantity, chitosan - obtained by deacetylation of chitin - stands as the sole nitrogen-containing cationic amino-sugar carbohydrate. This distinctively provides chitosan derivatives with plenty of opportunities in materials science. Particularly, its pH switchable solubility allowed the preparation of three-dimensional entangled nanofibrillated self-standing microspheres. These porous hydrogels behave as nano-reactors to confine exogenous nanoobjects within the polysaccharide network, including sol-gel metal alkoxide species, organometallic derivatives and isotropic and oriented nanoparticles. Besides, the interfacial interplay of chitosan with lamellar clay and graphene oxide allowed the penetration of the biopolymer inside of the galleries, which result in a complete delamination of the layered nanomaterials. The preserved gelation memory of chitosan in these formulations provides a way to access porous microspheres entangling exfoliated nanometric sheets. CO2 supercritical drying of functional hydrogel beads enabled efficient removal of water and other liquid solvents without wall collapsing, allowing large-scale preparation of millimetric hydrocolloidal microspheres with an open macroporous network. These functionalized lightweight biopolymer aerogels find applications in heterogeneous catalysis, sensing, adsorption, insulation and for the design of other sophisticated porous nanostructures. Beyond their tailorable molecular and textural-engineering, the possibility for macroscopic shaping of these intriguing nanostructures opens many new opportunities, especially in additive-manufacturing for soft and hybrid robotics.