Countless materials reversibly contract and swell as a chemical agent (e.g. hydrogen ions) is added to and then removed from the system:

https://www.researchgate.net/figure/Illustration-of-a-volume-transition-in-a-cross-linked-polybase-network-triggered-by-a-pH_fig1_47426820

These materials can, in principle, convert ambient heat into work cyclically and isothermally, in violation of the second law of thermodynamics. Here are two illustrations of how, by adding and removing hydrogen ions (H+), one can extract work from pH-sensitive polymers:

Figure 4 here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1367611/pdf/biophysj00645-0017.pdf

Figure 16A here: https://pubs.acs.org/doi/pdf/10.1021/jp972167t.

Adding and removing H+, per se, consumes no work if done QUASISTATICALLY. This means that the work lost e.g. in adding is compensated by the work gained in removing, and the net work involved is zero. So lifting a weight is the net work extracted from the cycle. The second law of thermodynamics is clearly violated.

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Pentcho Valev

An obviously absurd corollary of the second law of thermodynamics:

"The use of a catalyst does not affect the position and composition of the equilibrium of a reaction, because both the forward and backward reactions are sped up by the same factor." https://en.wikipedia.org/wiki/Le_Chatelier%27s_principle

Scientists should have noticed the obvious absurdity of this particular corollary of the second law of thermodynamics long ago, and applied reductio ad absurdum: Since the corollary is absurd, the underlying premise, the second law of thermodynamics, is false. Consider the dissociation-association reaction
A ⇌ B + C
which is in equilibrium. We add a catalyst and it starts splitting A - the rate constant of the forward (dissociation) reaction increases by a factor of, say, 745492. If the second law of thermodynamics is obeyed, the catalyst must increase the rate constant of the reverse (association) reaction by exactly the same factor, 745492. But this is insane! The reverse reaction is entirely different from the forward one: B and C must first get together, via diffusion, and only then can the catalyst join them to form A. Catalysts don't speed up diffusion!

Far from speeding up the forward and reverse reactions "by the same factor", here a catalyst speeds up only the forward, 2H+ → H_2, and SUPPRESSES the reverse reaction, H_2 → 2H+ (violation of the second law of thermodynamics par excellence):

Yu Hang Li et al. Unidirectional suppression of hydrogen oxidation on oxidized platinum clusters https://www.nature.com/articles/ncomms3500

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Pentcho Valev

That catalysts can shift chemical equilibrium, thereby violating the second law of thermodynamics, was my first heretical idea, about 30 years ago. Journals used to reject my submissions, as it were, before receiving them. Still the idea is correct:

https://youtu.be/usAPBgT3aDc?t=1101

"In 2000, a simple, foundational thermodynamic paradox was proposed: a sealed blackbody cavity contains a diatomic gas and a radiometer whose apposing vane surfaces dissociate and recombine the gas to different degrees (A_2 ⇌ 2A). As a result of differing desorption rates for A and A_2 , there arise between the vane faces permanent pressure and temperature differences, either of which can be harnessed to perform work, in apparent conflict with the second law of thermodynamics. Here we report on the first experimental realization of this paradox, involving the dissociation of low-pressure hydrogen gas on high-temperature refractory metals (tungsten and rhenium) under blackbody cavity conditions. The results, corroborated by other laboratory studies and supported by theory, confirm the paradoxical temperature difference and point to physics beyond the traditional understanding of the second law." https://link.springer.com/article/10.1007/s10701-014-9781-5

"A simple device is introduced that utilizes the phenomenon of epicatalysis to establish a stationary temperature difference by which ambient environmental thermal energy might be converted into useful work. [...] Traditional catalysis is a central pivot around which much of the industrial and biological worlds turn. Positive catalysts satisfy three general principles. First, they increase reaction rates by providing lower activation energies for rate-limiting steps. Second, they are not consumed by their net reactions although they are intimately involved in them. Third, they do not alter final thermodynamic equilibria of their reactions. Epicatalysts bend this third principle in that they shift the final gas-phase equilibria of reactions." D. P. Sheehan, T. M. Welsh, Epicatalytic thermal diode: Harvesting ambient thermal energy, Sustainable Energy Technologies and Assessments, Volume 31, February 2019, Pages 355-368 https://www.sciencedirect.com/science/article/pii/S2213138818301838

There is no separate group of "epicatalysts" - actually all catalysts shift the equilibrium and so violate the second law of thermodynamics (even though in most cases the effect is difficult to detect). I believe that a major function of enzymes, apart from speeding up metabolic reactions, is to make some of these reactions unidirectional: the forward reaction is catalyzed, the reverse is not.

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